WO2016184433A1

WO2016184433A1 - Pur and/or pir composite panel and method for continuous production of same

Info

Publication number: WO2016184433A1
Application number: PCT/CN2016/082983
Authority: WO
Inventors: Heng Huang; Raymond Chen
Original assignee: Honeywell International Inc.
Priority date: 2015-05-21
Filing date: 2016-05-23
Publication date: 2016-11-24
Also published as: CN105440302A

Abstract

Provided are PUR and/or PIR composite panel and preparation method thereof. The components of the composition are selected such that the ratio of the rising height of the foam at the contact time when the foam is contacting with the upper layer to the maximum free rising height is equal to or above 65%, preferably equal to or above 75%, thereby improving the anisotropy and dimensional stability of the composite panel produced in a continuous production line.

Description

PUR AND/OR PIR COMPOSITE PANEL AND METHOD FOR CONTINUOUS PRODUCTION OF THE SAME

FIELD

The present invention relates to the technical field of a polyurethane or polyisocyanurate composite panel. Specifically, the present invention relates to a polyurethane or polyisocyanurate composite panel produced by a continuous production line having improved dimensional stability, and a method for the continuous line production of the polyurethane or polyisocyanurate composite panel.

BACKGROUND

Polyurethane (PUR) composite panels generally comprise an upper layer, a bottom layer, and a foam layer between the upper and bottom layers. These panels are widely applied in the construction materials field, due to their advantages such as low cost and good heat insulation and sound insulation effects. In view of the higher flame retardant standards and requirements for the PUR composite panel, the use of PUR modified polyisocyanate (PIR) foamed plastic is particularly favored, due to its low combustion and better fire resistant performance than common PUR. However, composite panels comprising PUR or PIR, in particular PIR, produced by a continuous production line, exhibit uneven compressive strength distribution in each direction, especially relatively low compressive strength in the thickness direction, which results in the PUR or PIR composite panel having poor dimensional stability as a result of the tendency of the foam to shrink in thickness direction under the effect of the atmospheric pressure during the service cycle.

For the composite panel comprising PUR or PIR, dimensional stability is critical to performance. Thus, there is an urgent need to improve the dimensional stability of such composite panels produced by a continuous production line, in particular the anti-compressive capability in the thickness direction. In the past, those skilled in the art made the following attempts, including:

1) Adjusting the reaction formulation, such as adjusting the ratio of polyol or polyol mixture, silicon surfactant, catalysts, blowing agents, and other isocyanate components；

2) Changing the design of the composite panel structure, such as adding a reinforced filament to enhance the anti-deformation ability, improve dimensional stability, and thus prolong the service life such as in Chinese Patent Publication CN203222901U；

3) Increasing the density of foam, as it is well-known in the art that the higher density of foam will obtain higher compressive strength, thereby alleviating the problem of dimensional stability to some extent.

Although the above solutions alleviate the problem of dimensional stability to some extent, they are quite complex in operations, having higher costs, or are not suitable for the continuous line production.

Regarding the blowing agent in the continuous production of the PUR composite panel, 141b and pentane are common physical blowing agents. An environmental friendly composite material was also disclosed in Chinese Patent Publication CN102532456B, wherein the physical blowing agent is a blowing agent blend comprising 365mfc/134a in which 365mfc accounts for 93 wt％of the mixture； however, the focus of this application relates to environmental protection and is not directed to improving the properties of PUR composite panels produced in a continuous production line.

SUMMARY

The object of the present invention is to improve the compressive strength of the a composite panel comprising PUR and/or PIR produced by a continuous production line, thereby further improving the dimensional stability of the PUR and/or PIR composite panel.

To achieve the above object, according to one aspect of the present invention, there is provided a PUR and/or PIR composite panel at least comprising an upper layer, a bottom layer, and an inner layer between the upper and bottom layers, wherein the inner layer comprises a PUR and/or PIR foam which is produced using a blowing agent composition to produce the foam in a continuous composite panel production line, the components of the blowing agent composition are selected such that the ratio of the rising height H_T of the foam at the contact time when the foam is contacting the upper layer to the maximum free rising height H_max is equal to or above 65％, preferably equal to or above 75％.

The blowing agent composition comprises two components, component I and component II, wherein the component I is selected from a group of HFC-245fa, HFO-1233zd (E) , HFO-1233zd (Z) , HFO-1234ze (E) , HFO-1234ze (Z) , HCFC-22, HCFC-142b, CO₂, HFC-227ea， HFC-134a, and the component II is selected from a group of HCFC-141b, HFC-365mfc, 1336mzzm (Z) , HFO-1336mzzm (E) , methyl formate, methylal, n-pentane, cyclo-pentane and iso-pentane.

In the PUR and/or PIR composite panel, the weight percentage of the component I in the blowing agent composition can be 20％or greater, or from 20％to 80％, or from 20％to 75％, or from 20％to 50％； preferably 25％or greater, or from 25 to 80％, more preferably from 25％to 75％, or from 25％to 50％, or from 25 to 38％.

In the PUR and/or PIR composite panel, the oxygen index of the inner layer can be above 23.

In the PUR and /or PIR composite panel, the ratio of the compressive strength in thickness direction (C_x) of the inner layer to the total compressive strength in three directions (C_x+y+z) can be greater than28％, preferably greater than 30％.

In the PUR and/or PIR composite panel of the present invention, the PURand/or PIR foams are prepared from a foamable composition which generally includes one or more components capable of forming a foam. The PUR and/or PIR foam can be prepared by adding the blowing agent of the invention (either directly or indirectly) to a foamable composition and reacting the foamable composition under conditions to form a foam, as is well known in the art. Preferably the foam is produced by combining an isocyanate, a polyol or polyol mixture and the blowing agent of the invention. The composition can comprise catalysts, surfactants and other optional components such as a flame retardant and a colorant and the like.

The foam formulation can be provided in two components, the “A” component and the “B” component. The “A” component comprises the isocyanate. The “A” component may additionally and optionally comprise additional components such as surfactants or blowing agents. The “B” component comprises the polyol or polyol mixture, the catalyst and the blowing agent. It may also comprise a surfactant, a flame retardant and other isocyanate reactive components. The “A” component and the “B” component can be provided separately or can be preblended. During the manufacturing process of the PUR and/or PIR composite panel, the ” A” and “B” components are poured into the panel to produce the PURand /orPIR foam layer, wherein any organic polyisocyanate, preferably aromatic polyisocyanate, can be used for the synthesis of the PURand/orPIR foams. The polyol can be polyester polyol, polyether polyol, and other examples include copolyol. In the case of the PIR foam, the aromatic polyester polyol can be used.

According to another aspect of the present invention, there is provided a method for the continuous production of the PUR and/or PIR composite panel at least comprising an upper layer, a bottom layer, and an inner layer between the upper and bottom layers, wherein the inner layer comprises PUR and/or PIR foams, said method including using a blowing agent composition to produce the foam in a continuous composite panel production line to produce the inner layer, the components of the blowing agent composition are selected such that the ratio of the rising height H_T of the foam at the contact time when the foam is contacting the upper layer to the maximum free rising height H_max is equal to or above 65％, and preferably equal to or above 75％.

In the above method, the blowing agent composition can comprise two components, component I and component II, wherein the component I is selected from a group of HFC-245fa, HFO-1233zd (E) , HFO-1233zd (Z) , HFO-1234ze (E) , HFO-1234ze (Z) , HCFC-22, HCFC-142b, CO₂, HFC-227ea， HFC-134a, and the component II is selected from a group of HCFC-141b, HFC-365mfc, 1336mzzm (Z) , HFO-1336mzzm (E) , methyl formate, methylal, n-pentane, cyclo-pentane and iso-pentane.

In the above method, the weight percentage of the component I in the blowing agent composition can be 20％or greater, or from 20％to 80％, or from 20％to 75％, or from 20％to 50％； preferably 25％or greater, or from 25 to 80％, more preferably from 25％to 75％, or from 25％to 50％, or from 25 to 38％.

Preferably the blowing agent composition comprises component I and component II, wherein the component I is HFC-245fa and the component II is HCFC-141b, or the component I is HFO-1233zd and the component II is selected from n-pentane, cyclo-pentane or iso-pentane.

In the above method, the weight percentage of the component I in the blowing agent composition can be in the range of from 25％to 50％.

Preferably, the blowing agent composition comprises component I and component II, wherein the component I is HFC-245fa and the component II is HCFC-141b, and the weight percentage of the component I in the blowing agent composition is in the range of from 25％to 38％.

In the above method, the oxygen index of the inner layer can be above 23.

According to another aspect of the present invention, there is provided a method for continuous production of the PUR and/or PIR composite panel at least comprising an upper layer, a bottom layer, and an inner layer between the upper and bottom layers, wherein the inner layer comprises PUR and/or PIR foams, said method including using a blowing agent composition to produce the foam in a continuous composite panel production line to produce the inner layer, the components of the blowing agent composition are selected and the amount of the foamable composition and the speed of the continuous panel production line are adjusted such that the ratio of the rising height H_T of the foam at the contact time when the foam is contacting the upper layer to the maximum free rising height H_max is equal to or above 65％, and preferably equal to or above 75％.

The above method further comprises adjusting the pour-in density of the foamable composition, such that the ratio of the rising height H_T of the foam at the contact time when the foam is contacting the upper layer to the maximum free rising height H_max is equal to or above 65％, and preferably equal to or above 75％.

Moreover, in the above PUR and/or PIR composite panel or the method for the production of the PUR and/or PIR composite panel, the blowing agent composition comprises component I and component II, wherein the component I is selected from the group consisting of HFC-245fa, HFO-1233zd, HCFC-22, HCFC-142b, CO₂, HFC-227ea, and HFC-134a, and the component II is selected from the group consisting of HCFC-141b, HFC-365mfc, 1336mzzm, n-pentane, cyclo-pentane, and iso-pentane. The weight percentage of the component I in the blowing agent composition can be 20％or greater, or from 20％to 80％, or from 20％to 75％, or from 20％to 50％； or 25％or greater, or from 25 to 80％, or from 25％to 75％, or from 25％to 50％, or from 25 to 38％.

Furthermore, in the above PUR and/or PIR composite panel or the method for the production of the PUR and/or PIR composite panel, the ratio of the rising height H_T of the foam at the contact time when the foam is contacting the upper layer to the maximum free rising height H_max is equal to or above 65％, preferably equal to or above 75％； and alternatively, below or equal to 95％or 90％.

During the production of PUR and/or PIR foams, water can be added as an additional blowing agent.

With the addition of component I comprising HFC-245fa, HFO-1233zd, HCFC-22, HCFC-142b, CO₂, HFC-227ea, or HFC-134a and the combination thereof as the blowing agent composition, the method for continuous production of the PUR and/or PIR composite panel in the present invention is particularly suitable for the production of PUR and/or PIR foams originally blown and prepared with component II solely comprising HCFC-141b, HFC-365mfc, 1336mzzm, n-pentane, cyclo-pentane, and iso-pentane as the blowing agent, thereby significantly improving the compressive strength distribution in three directions, in particular the compressive strength in thickness direction.

Further, herein, ； the term "free rising" refers to foamable composition growing and expanding freely without restriction (compression) until the end of the blowing process； the term "maximum free rising height" refers to the maximum height to be achieved by the foamable composition under conditions of "free rising" ； the term "contact time" refers to the time for the foamable composition to contact the upper layer in the continuous production line； and the gel time refers to the time for the foamable composition to be converted into a solid gel.

In addition, herein, the dimensional stability is tested according to GB/T8811-2008 standard； the compressive strength is tested according to GB/T8813-2008 standard； the oxygen index is tested according to GB/T2406-2008； the density is tested according to GB/T6343-2009 standard； and the thermal conductivity is tested according to GB/T10294-2008 standard.

The benefits of the present invention are at least as follows:

1) During the foam formation, the higher ratio of the foam rising height at contact time (contact the upper layer of composite panel) to the free rising height, the more tendency for foam cell to be isotropic, which result in increasing the total compressive strength of the PUR composite panel, in particular, the compressive strength in thickness direction. As a result, the compressive strength distribution is significantly improved, and an increase in compressive strength in thickness direction renders an increase in the ratio of the compressive strength in thickness direction to the total compressive strength in three directions. Moreover, the isotropic foams are also good for avoiding foam cell deformation. Therefore, the dimensional stability of the composite panel is improved.

2) The composite panel has better compressive strength even with the density of foam layer of composite panel slightly decreased.

3) The higher foam rising decreases the foaming rolling probability which may result in air bubble.

4) The observed faster rate of foam rise is particularly preferred for a continuous PUR and/or PIR composite panel line, especially for PIR thicker plate (>100mm) in a high speed production line.

5) The higher percentage of foam rising height, the lower pressure in mould, so that the de-mould time is reduced, the panel line speed is increased, and thus the production efficiency is further improved.

DRAWINGS

Hereinafter the specific embodiments of the present invention will be illustrated with the following Figures:

Figure 1 represents the relationship between the rising height of the foamable composition and time in the PUR system and the PIR system；

Figure 2 represents the possible cell foam orientation in a cubic mould；

Figure 3 diagrammatically represents a continuous PUR composite panel production line；

Figure 4 represents the possible cell foam orientation in a continuous PUR composite panel production line；

Figure 5 represents various directions of the PUR composite panel in a continous production line and the production line directions；

Figure 6 diagrammatically represents, the relationship between the reaction time and the height ratio (i.e. the ratio of the rising height to the maximum free rising height) in the 141b blowing agent system and the 141b/245fa blowing agent composition system with the same feeding conditions；

Figure 7 diagrammatically represents, the relationship between the reaction time and the rising height in the 141b blowing agent and the 141b/245fa blowing agent composition with the same contact time；

Figure 8 represents a simulated mould in a laboratory；

Figure 9 represents, the ratio of the rising height at contact time to the maximum foam rising height in the 141b/235fa blowing agent composition system with different amount of 245fa, and

Figure 10 represents, the ratio of the rising height at contact time to the maximum foam rising height in the HFO-1233zd/cyclopentane blowing agent composition system with different amount of HFO-1233zd.

DETAILED DESCRIPTION

Regarding the main reactions in a foaming process,

There are generally three kinds of reaction in PUR foam production: reaction which are: (1) between polyol and isocyanate to generate polyurethane groups, which is also called PUR reaction； reaction (2) between isocyanate and water to generate polyurea groups and CO₂, which releases great amount of heat, gasifies the physical blowing agent, makes the reacting liquid expanding, and this is also called "cream or elicitation" in the art； and the trimerization reaction (3) between isocyanates to generate polyisocyanate groups, which is also called PIR reaction.

The skilled person will therefore appreciate that the composites and methods of the present application comprising foam produced using reactions (1) and/or (3) as set out above. When the blowing agent composition further comprises water as an additional blowing agent, the composites and methods of the present application may additionally comprise foam produced using reaction (2) as set out above.

In common PUR composite panel production, the–NCO/-OH ratio is usually 1.0 to ensure that the isocyanate reacts completely with the polyol and water. In order to improve the fire resistant performance of the composite panel, the–NCO/-OH ratio is usually 1.5 to 4.0 to leave more–NCO group for trimerization reaction and to provide more PIR groups. The PIR reaction produces a foam having better fire resistant performance and compressive strength. In addition, water is generally controlled to prevent consumption of the isocyanates by excess water. Thus, the water content is generally controlled at a lower level in the PIR system, so that the early phase reaction is quite slow and the late phase reaction is suddenly faster in the PIR system.

Figure 1 shows a schematic view of the relationship between the rising height of the foamable composition and time in the PUR system and the PIR system, wherein the dotted line shows the gel time. As mentioned above, since the early phase reaction is quite slow and the late phase reaction is faster in the PIR system, the observed foam rise height is lower in the PIR system than the PUR system at the same gel time. As described herein below, this renders the problems of compressive strength in thickness direction and the dimensional stability more prominent in the PIR system, during the continuous composite panel production.

Relationship between foam cell orientation and compressive strength

In reference to Figure 2, the mould is without a covering. Regarding the free rising PUR foam, the foam cell is substantially in the ellipsoidal shape during the formation and growth of the foam cell. Since the foam cell is affected by the mould at both sides, the foam cell is substantially in the ellipsoidal shape before contacting the top panel (because both sides are restricted and thus the foam cell mainly rises upward) . As illustrated in Figure 2, the main rising direction is along the arrow D, and thus the long axis of the ellipsoidal foam cell 2 is along the thickness direction X.

It has been proved that, for a ellipsoidal foam cell, the compressive strength is the greatest in the long axis direction (the compressive strength can be tested according to GB/T8813-2008) . It can be presumed that the direction of the maximum compressive strength is in the long axis direction of foam cell. Thus, it shall be noted that a method of increasing the compressive strength in thickness direction can be conceived to increase the amount or ratio of the foam cell in the longitudinal orientation.

With respect to continuous line production

Figure 3 illustrates a schematic view of a polyurethane composite panel production line, wherein the upper layer 32 is supported by a plurality of support rollers 31, the bottom layer 33 is spread on-site； the upper layer 31 and the bottom layer 33 are synchronously driven by a conveyor and translated in the right direction to go through the laminating roller 34. The foamable composition 35 is continuously poured to the space between the upper layer and the bottom layer by a foaming equipment distributor 36. As illustrated in the figure, T₂ is the time when the foamable composition rises and contacts the upper layer 31, which is also called the contact time in the text, and T₁ is the gel time.

During continuous production, the laminating effect on the upper layer occurs simultaneously with the expanding of the foam forming components of the foamable composition. The foamable composition is poured to the bottom surface of the composite panel, and the foaming reactions take place simultaneously or sequentially. The heat generated by the exothermic reaction will result in the expansion of the blowing agent, causing the foamable composition to rise up until it contacts the upper layer. Generally, the gel time of the foamable composition is constant for the specific components of the foamable composition. It has been proved in production and practice that the time when the foamable composition rise in thickness direction contacting the upper layer (contact time) is optimally 5 seconds before the gel time, i.e. T₁-T₂＝5s. It will be appreciated that the foaming reaction will not stop once the foamable composition contacts the upper layer but will continue thus causing the foamable composition to continue to expand until the reaction is complete and the foam gels.

In reference to Figures 4 and 5, Figure 4 illustrates the possible microstructure of the inner layer of the PUR composite panel produced by a continuous production line. Figure 5 illustrates each direction of the composite panel. Herein, M or Y direction is the direction of the production line, X is the thickness direction, and Z is the width direction.

During the compressive strength test, it can be found that the compressive strengths of the PUR composite panel produced by a common continuous production line vary greatly in different directions. Specifically, in one embodiment, the strength in thickness direction X is C_x＝92kPa, the strength in the width direction Z is C_z＝98kPa, and the strength in the processing or pressing direction is C_y＝221kPa. Thus, the compressive strength is greater in the Y direction.

Blowing agent system and the comparison between the HCFC-141b+HFC-245fa blowing agent system

Figure 6 diagrammatically shows that under equivalent processing conditions , the relationship between the reaction time and the height ratio (the height ratio is the ratio of the actual rising height to the maximum free rising height H_max) in the HCFC-141b (referred to as 141b) blowing agent and 141b blended with HFC-245fa (referred to as 245fa) blowing agent (hereinafter referred to as the 141b/245fa system) , without considering contacting the upper layer. In this case it will be clear that the foam freely rises and expands without restriction (compressing) until the end of the foaming process when the maximum height that can be achieved is the maximum free rising height H_max. Experiments have proved that when 245fa is blended according to the present invention, the point before 5 seconds of the gel time is defined as T point where foams blown by the 141b+245fa blowing agent system have a significant higher rise than that of the 141b blowing agent system.

In particular, the following experiments have proved that when the ratio of the rising height H_T at contact time to the maximum free rising height H_max is equal to or above 65％, and preferably equal to or above 75％, the compressive strength distribution of the foam layer in three directions would be more desirable, with increased compressive strength in thickness direction and improved dimensional stability.

For the convenience of understanding, in reference to Figure 7, since the foamable composition rises faster in the system using the 141b+245fa blowing agent, the 141b/245fa system at the same contact time can also achieve the same rising height of the 141 system even with less feeding rate. Thus, in order to achieve the same contact time, in the system using 141b+245fa blowing agent, the amount of the foam forming components in the foamable composition (while not substantially affecting the density of the final foam layer) can be reduced . In this case, it can be clearly seen that the upward expanding height H1 of the 141b/245fa blowing agent system after the contact time T₂ is lower than H2 in the 141b system. In the case of the continuous production line, after contacting the upper layer, the 141b system would rise more along the Y direction, , thereby increasing the amount or proportion of the foam cell long axis taking the Y direction. Therefore, as compared with the sole 141b system, the foam cell maintaining the X orientation in the 141b/245fa is greater in amount or proportion, and accordingly the strength in the X direction is also greater.

Laboratory experiments

The applicant attempted to simulate the process of continuous production of the PUR foam panel with different blowing agent systems in the laboratory. As illustrated in Figure 8, typically foam was blown in a cubic mould or container with six faces. When the polyol and isocyanate blends were poured into the container, the liquid expanded in each direction and contacted the top surface, and then gelled to solid foam.

To simulate the continuous production line in the laboratory, there is provided a cubic mould ABCDEFGH, wherein ACGE side is left open. When the foam contacts the upper layer, it tends to flow to the ACGE direction under the effect of sufficient pressure. Specifically, the foam was produced by firstly, opening the ACDB and ACGE sides and pouring in the blowing agents and foamable compositions as defined below. It will be noted from table 1 below that the amounts of the components of the foamable composition, specifically the K15 metal catalyst and the blowing agent were adjusted to ensure that the gel time is almost the same for each composition, and the contact time is set as 5 seconds before the gel time. Subsequently, the ACDB side is closed and the ACGE side remains open and then blow the reaction and test the final product.

Experiment 1: 141b system and 141b /245fa system

Formulation

Table 1 Formulation

Components	Names	1#	2#	3#	4#
GR 835G	Sugar based polyether polyol	50	50	50	50
PS2412	Polyester polyol		50	50	50	50
TCPP	Flame retardant	16	16	16	16

PC5	Amine catalyst	0.3	0.3	0.3	0.3
K15	Metal catalyst	1.50	1.60	1.65	1.85
DC193	Surfactant	2.0	2.0	2.0	2.0
Water		1.0	1.0	1.0	1.0
141b	Blowing agent component I	24.0	18.6	12.8	6.6
245fa	Blowing agent component II		6.2	12.8	19.9
PMDI	BASF M20S	210	210	210	210

The four groups of formulations use substantially the same proportions of 245fa in replacement of 141b, which account for 0％, 25％, 50％and 75％of the total blowing agent, and are marked as samples #1, #2, #3 and #4, respectively. In addition, the total weight of the blowing agent and the weight of the catalyst are adjusted to obtain the similar gel time and core or inner layer density.

Table 2 245fa ratio/gel time/core density

As illustrated in Figure 9, the instrument FOAMAT was used to record the relation between the 245fa ratio in the blowing agent composition and the foam rising height ratio (i.e. the H/H_max ratio of the foam rising height H to the maximum free rising height H_max) , wherein the rising height H_T at contact time T₂which is 5 seconds before the gel time, is marked. The figure shows that when 25％245fa is used, the H_T/H_max ratio of the foamable composition's rising height at contact time to the maximum free rising height is 65％. With the increase of the amount of 245fa, the ratio of the rising height at the contact time to the maximum free rising height is further increased.

Table 3 Compressive strength of each sample

1#

2#

3#

4#

Overall density kg/m³	54.5	51.8	47.7	46.4
Core density kg/m³	40.6	39.2	38.8	38.5
Compressive Strength X kPa	98	135	148	142
Compressive Strength Y kPa	188	159	151	148
Compressive Strength Z kPa	91	94	97	106

Compressive strength was measured according to the GB/T8813-2008 standard

Experiments show that even with lower pour-in density and core density, the 245fa/141b system still has relatively good compressive strength in X direction, which is extremely important for the continuous production of the PUR composite panel.

Table 4 The total compressive strength in three directions and the ratio of the compressive strength in thickness direction to the total compressive strength

As can be seen from Table 4, adding the 245fa blowing agent to the current 141b blowing agent in the amounts set out in table 4 increases the total compressive strength (even though the foam density decreases) . Moreover, in the case of the blowing agent composition, the compressive strength in thickness direction and its ratio in the total compressive strength in three directions (i.e. the compressive strength C_X+Y+Z which is the sum of the compressive strength in X, Y and Z directions) are increased. The final product of the foam panel has more evenly distributed compressive strength. . Thus, the present invention can effectively improve the anisotropy of the PUR composite panel, thereby increasing the compressive strength in thickness direction and improving the dimensional stability thereof.

Table 5 Dimensional stability of each sample

	1#	2#	3#	4#
245fa ratio by weight in Blowing agent ％	0	25	50	75
Dimensional stability ％under the same conditions	6.80	2.55	2.21	2.83

The dimensional stability was tested according to GB/T8811-2008 standard, the sample was placed under the experimental condition of 70 degrees Celsius, with 95％relative humidity for 24 hours and the dimensional difference of the sample has been tested. Thus, it can be seen from the table that the dimensional stability is better when the 245fa ratio is above 25％and preferably 50％.

Experiment 2: Cyclopentane and cyclopentane/trans HFO-1233zd system

Similar experiments can also be performed between the cyclopentane system and the cyclopentane/trans HFO-1233zd system. The experimental results are as follows.

Formulation

Table 6 Formulation

Components	Names	1#	2#	3#	4#
GR 835G	Sugar based polyether polyol	50	50	50	50
PS2412	Polyester polyol		50	50	50	50
TCPP	Flame retardant	16	16	16	16
PC5	Amine catalyst	0.3	0.3	0.3	0.3
K15	Metal catalyst	1.60	1.70	1.85	2.05
DC193	Surfactant	2.0	2.0	2.0	2.0
Water		1.0	1.0	1.0	1.0
Cyclopentane	Blowing agent component I	15	12.7	9.8	5.7
HFO-1233zd	Blowing agent component II		4.3	9.8	17.2
PMDI	BASF M20S	210	210	210	210

The four groups of formulations use substantially the same proportions of HFO-1233zd in replacement of cyclopentane, which account for 0％, 25％, 50％and 75％of the total blowing agent, and are marked as samples #1, #2, #3 and #4, respectively. Likewise, the weight of the blowing agent and the weight of the catalyst were adjusted to obtain the similar gel time and core density.

Table 7 HFO-1233zd ratio/gel time /core density

	1#	2#	3#	4#
HFO-1233zd ratio by weight in Blowing agent ％	0	25	50	75
Gel time	75	78	77	77
Core density	34.8	35.4	35.7	5.8

As illustrated in Figure 10, the instrument FOAMAT was used to record the relation between the HFO-1233zd ratio in the blowing agent composition and the foam rising height ratio (i.e. the H/H_max ratio of the foam rising height H to the maximum free rising height H_max) , wherein the rising height H_T at the contact time which is 5 seconds before the gel time, is marked. The figure shows that when 25％HFO-1233zd is blended with cyclopentane, the H_T/H_max ratio of the foamable composition's rising height at contact time to the maximum free rising height is 65％. When the amount of HFO-1233zd is increased, the ratio of the rising height at the contact time to the maximum free rising height is further increased.

Table 8 Compressive strength of each sample

	1#	2#	3#	4#
Overall density kg/m³	56.8	53.7	49.4	48.2
Core density kg/m³	42.4	42.1	41.8	39.3
Compressive Strength X kPa	77	152	179	156
Compressive Strength Y kPa	233	221	215	208
Compressive Strength Z kPa	163	153	152	136

Compressive strength was measured according to the GB/T8813-2008 standard

Experiments show that even with lower pour-in density and core density, the HFO-1233zd/cyclopentane system still has relatively good compressive strength in X direction.

Table 9 The total compressive strength in three directions and the ratio of the compressive strength in thickness direction to the total compressive strength

As can be seen from Table 9, adding HFO-1233zd blowing agent to the current cyclopentane blowing agent in the amounts indicated in table 9 increases the total compressive strength (even though the foam density decreases) . Moreover, in the case of the blowing agent composition, the compressive strength in thickness direction and its ratio in the total compressive strength are increased. The final product of the foam panel has more evenly distributed compressive strength. Thus, the present invention can effectively improve the anisotropy of the PUR composite panel, thereby increasing the compressive strength in thickness direction and improving the dimensional stability thereof.

Table 10 Dimensional stability of each sample

	1#	2#	3#	4#
HFO-1233zd ratio by weight in Blowing agent ％	0	25	50	75
Dimensional stability ％under the same conditions	10.7	3.58	2.87	3.05

The dimensional stability was tested according to GB/T8811-2008 standard, the sample was placed under the experimental condition of 70 degrees Celsius, with 95％relative humidity for 24 hours and the dimensional difference of the sample has been tested. Thus, it can be seen from the table that the dimensional stability is better when the HFO-1233zd ratio is above 25％and preferably round 50％.

Conclusions

It shall be understood that under the inspiration of the above experiments, those skilled in the art can modify the components of the blowing agent and calculate the ratio of each blowing agent in the composition and the relationship between the foamable composition’s rising height at contact time and the maximum free rising height according to the experimental method in the present invention, and select the suitable blowing agent composition to fulfill the same technical purpose. The applicant comes to the conclusions after repetitive experiments that no matter how the components of the blowing agent composition are set, as long as the H_T/H_max ratio of the foamable composition’s rising height H_T at the contact time to the maximum free rising height H_max is equal to or above 65％, and preferably equal to or above 75％, the compressive strength in thickness direction will be significantly improved.

It shall be understood that the experimental method disclosed in the present invention can be repeatedly carried out on various combinations of the blowing agents to obtain the corresponding experimental results. The applicant has proved with experiments that the following components of the blowing agent composition are preferred. The blowing agent comprises component I and component II. The examples of component I include, but are not limited to, HFC-245fa, HFO-1233zd, trans HFO-1233zd, cis-HFO-1233zd, trans-HFO-1234ze, cis-HFO-1234ze, HCFC-22, HCFC-142b, CO₂, HFC-227ea, and HFC-134a； and the examples of component II include, but are not limited to, HCFC-141b, HFC-365mfc, HFO-1336mzzm, trans-HFO-1336mzzm, cis-HFO-1336mzzm, methyl formate, methylal, n-pentane, cyclo-pentane, and iso-pentane. That is, any combination of the above components in component I and component II at suitable proportions as the blowing agent composition resulting in the ratio of the rising height H_T of the foamable composition in the inner layer at the contact time when the foamable composition is contacting the upper layer and the maximum free rising height H_max is equal to or above 65％, preferably equal to or above 75％, can effectively improve the dimensional stability in thickness direction. For all combinations, the experimental study has found out that when the weight percentage of component I in the blowing agent composition is 20％or greater, preferably from 20％to 75％, more preferably from 20％to 50％, the compressive strength distribution in each direction is more satisfactory, and the dimensional stability is better. Therefore, with respect to the blowing agent composition not verified by experiments, the components of the blowing agent can be set in reference to above proportions.

It shall be understood that for a continuous production line, one or more of the foamable composition content, the pour-in density of the foamable composition, and the production line speed can be adjusted so that the foamable composition sufficiently rises before the contact time, thereby achieving the purpose that the ratio of the rising height H_T at the contact time to the maximum free rising height H_max is equal to or above 65％, preferably equal to or above 75％. The selection of the foamable composition content, the pour-in density of the foamable composition, and the production line speed are selected based on the purpose of achieving the same contact time. Specifically, when a preferred solution of the components of the blowing agent composition is obtained through laboratory experiments, the parameters such as the foamable composition content, the pour-in density of the foamable composition, and the production line speed can be adjusted to obtain the similar contact time, and the ratio of the rising height H_T at the contact time to the maximum free rising height H_max is equal to or above 65％, preferably equal to or above 75％. The applicant has surprisingly found out that even though the foamable composition content is reduced and the production line speed is increased in the case of the blowing agent composition, it can also achieve greater compressive strength in thickness direction.

It shall be understood that the upper layer and the bottom layer of the composite panel of the present invention can be made of any commonly used materials in the art. However, the materials more suitable for the upper layer and the bottom layer in the present invention include, but are not limited to, steel, aluminum, paper or plywood. Moreover, the inner layer of the present invention is more preferably composed of fire resistant material with an oxygen index of greater than 23. Further, water in the above various formulations is used as an additional blowing agent to promote the foaming process.

In addition, when selecting the blowing agent components, other than the increase of the compressive strength in thickness direction, it should also be taken into consideration of the compressive strength in other directions not being substantially affected. Although the compressive strength in thickness direction is desirable, it shall be noted that when the C_x/C_x+y+z ratio of the compressive strength in thickness direction to the total compressive strength in three directions is over 28％, preferably over 30％, in the experiments, the dimensional stability in each direction tends to be reasonable, thereby significantly improving the anisotropy. Moreover, the improvement of the dimensional stability of the blowing agent in the present invention may also be resulted from for example, the release of more internal stress or internal pressure during the foaming process.

t shall be understood that the specific embodiments described above are only intended to illustrate the principles of this patent more clearly, wherein each component is specified to make the principles of the present invention more easily understood. Those skilled in the art can readily make various modifications to the present invention as long as the modifications do not go beyond the scope of disclosure contained the present invention. Therefore, it shall be understood that the scope of the present invention should not be limited to the above specific Embodiments.

Claims

A polyurethane or polyisocyanurate composite panel at least comprising an upper layer, a bottom layer and an inner layer between the upper layer and the bottom layer, wherein the inner layer comprises polyurethane or polyisocyanurate foams, wherein the inner layer is produced by using a blowing agent composition to produce the foam in a continuous composite panel production line, the components of the blowing agent composition are selected such that the ratio of the rising height H_T of the foam at the contact time when the foam is contacting with the upper layer to the maximum free rising height H_max is equal to or above 65％, preferably equal to or above 75％.
The polyurethane or polyisocyanurate composite panel of claim 1, wherein the blowing agent composition comprises component I and component II and wherein the component I is selected from a group of HFC-245fa, HFO-1233zd (E) , HFO-1233zd (Z) , HFO-1234ze (E) , HFO-1234ze (Z) , HCFC-22, HCFC-142b, CO₂, HFC-227ea， HFC-134a, and the component II is selected from a group of HCFC-141b, HFC-365mfc, HFO-1336mzzm (Z) , HFO-1336mzzm (E) , methyl formate, methylal, n-pentane, cyclo-pentane and iso-pentane.
The polyurethane or polyisocyanurate composite panel of claim 1, wherein the blowing agent composition comprises component I and component II and wherein the component I is selected from the group consisting of HFC-245fa, HFO-1233zd, HCFC-22, HCFC-142b, CO₂, HFC-227ea, and HFC-134a, and the component II is selected from the group consisting of HCFC-141b, HFC-365mfc, 1336mzzm, n-pentane, cyclo-pentane, and iso-pentane.
The polyurethane or polyisocyanurate composite panel of claim 1, wherein the blowing agent composition comprises component I and component II and wherein the component I is HFC-245fa and the component II is HCFC-141b or otherwise the component I is HFO-1233zd and the component II is selected from n-pentane, cyclo-pentane or iso-pentane.
The polyurethane or polyisocyanurate composite panel of any preceding claim wherein the weight percentage of the component I in the blowing agent composition can be 20％ or greater, or from 20％ to 80％, or from 20％ to 75％, or from 20％ to 50％； or 25％ or greater, or from 25 to 80％, or from 25％ to 75％, or from 25％ to 50％, or from 25 to 38％.
The polyurethane or polyisocyanurate composite panel of any preceding claim, wherein the weight percentage of the component I in the blowing agent composition is in the range of from 25％ to 50％.
The polyurethane or polyisocyanurate composite panel of any preceding claim, wherein the blowing agent composition comprises component I and component II and wherein the component I is HFC-245fa and the component II is HCFC-141b, and the weight percentage of the component I in the blowing agent composition is in the range of from 25％ to 38％.
The polyurethane or polyisocyanurate composite panel of any preceding claim, wherein the oxygen index of the inner layer is above 23.
The polyurethane or polyisocyanurate composite panel of any preceding claim, wherein the ratio of the compressive strength in thickness direction (C_x) of the inner layer to the total compressive strength in three directions (C_x+y+z) is above 28％, preferably above 30％.
A method of line production of a polyurethane or polyisocyanurate composite panel at least comprising an upper layer, a bottom layer and an inner layer between the upper layer and the bottom layer, the inner layer comprises polyurethane or polyisocyanurate foams, wherein, said method including using a blowing agent composition to produce the foam in a continuous composite panel production line to produce the inner layer, the components of the blowing agent composition are selected such that the ratio of the rising height H_T of the foam at the contact time when the foam is contacting with the upper layer to the maximum free rising height H_max is equal to or above 65％, and preferably equal to or above 75％.
The method of claim 10, wherein the blowing agent composition comprises component I and component II, the component I is selected from a group of HFC-245fa, HFO-1233zd (E) , HFO-1233zd (Z) , HFO-1234ze (E) , HFO-1234ze (Z) , HCFC-22, HCFC-142b, CO₂, HFC-227ea， HFC-134a, and the component II is selected from a group of HCFC-141b, HFC-365mfc, 1336mzzm (Z) , HFO-1336mzzm (E) , methyl formate, methylal, n-pentane, cyclo-pentane and iso-pentane.
The method of claim 10, wherein the blowing agent composition comprises component I and component II and wherein the component I is selected from the group consisting of HFC-245fa, HFO-1233zd, HCFC-22, HCFC-142b, CO₂, HFC-227ea, and HFC-134a, and the component II is selected from the group consisting of HCFC-141b, HFC-365mfc, 1336mzzm, n-pentane, cyclo-pentane, and iso-pentane.
The method of claim 10, wherein the blowing agent composition comprises component I and component II and wherein the component I is HFC-245fa and the component II is HCFC-141b or otherwise the component I is HFO-1233zd and the component II is selected from n-pentane, cyclo-pentane or iso-pentane.
The method of any one of claims 10 to 13 wherein the weight percentage of the component I in the blowing agent composition can be 20％ or greater, or from 20％ to 80％, or from 20％ to 75％, or from 20％ to 50％； or 25％ or greater, or from 25 to 80％, or from 25％ to 75％, or from 25％ to 50％, or from 25 to 38％.
The method of any one of claims 10 to 14, wherein the weight percentage of the component I in the blowing agent composition is in the range of from 25％ to 50％.
The method of any one of claims 10 to 15, wherein the blowing agent composition comprises component I and component II and wherein the component I is HFC-245fa and the component II is HCFC-141b, and the weight percentage of the component I in the blowing agent composition is in the range of from 25％ to 38％.
The method of any one of claims 10 to 16, wherein the oxygen index of the inner layer is above 23.
The method of any one of claims 10 to 17, wherein the ratio of the compressive strength in thickness direction (C_x) of the inner layer to the total compressive strength in three directions (C_x+y+z) is above 28％, preferably above 30％.