CA1315658C - Laminate formed from a polyarylate sheet and a polycarbonate and/or polyester sheet - Google Patents

Abstract

LAMINATE FORMED FROM A
POLYARYLATE SHEET AND A
POLYCARBONATE AND/OR POLYESTER SHEET
ABSTRACT OF THE DISCLOSURE
Described herein are laminates formed from a layer of a polyarylate sheet and a layer of an aromatic polycarbonate, a polyester, or mixtures of these resin sheets. These laminates are suitable for use in glazing applications.

Description

LAMINATE FORMED FROM A
POLYARYLATE SHEET AND A

TECHNICAL_FIELD
This invention is directed to a lamina~e formed from a layer of a polyarylate sheet and 8 layer of ~ sheet of an aromatic polycarbonate, a thermoplastic polyester, or blends of these polymers.
` BACKGROUND OF THE INVENTION
Aromatic poly~arbonates, especially those formed from bisphenol-A and carbonyl chloride, and polyesters, such 8S poly(e~hylene terephthalate), are extensively used in glazing applications. That is, sheets m~de from these resins are used as windows, films, sky-lights, etc. However, in long-term exposure to ultraviolet ( W) light, the sheets become hazy. The h~ze is a micro cr~cking of the surface. This crazing results in a loss of mechanical properties and light transmission. A
solution to this problem has been to apply coatings to the sheets. The coating is hPlpful to some extent since it is able to protect the sheet against haze for 8 longer period of time than an uncoated sheet. However, crazing is still a problem. Also?
coating is expensive since special equipment is needed, and contained in the casting polymer are relatively large quantities of expensive UV
absorbers. Further, solvent contained in the coatin~ must be evaporated. `
Polyaryl~tes are polyesters derived from a dihydric phenol, particul~rly bisphenol-A and an aromatic dicarboxylic ~cid, particularly mixturPs of terephthalic a~d isophthallc acids. The .

.. ':

` ' 13~58 polyarylates are high ~emperature, high per$ormancP
thermoplastic polymers with 2 good combination of mechanical properties and are used to mold a variety of articles.
It is known that upon exposure to ultraviolet light polyarylates undergo the Photo-Fries rearrangement. Korshak et al ~n Synthesis and Properties of Self-Protecting Polyarylates, Journal of Polymer Science, Part A-l, Vol. 7, pages 157 to 172 (1969) describe a mechanism to explain what happens when polyarylates are exposed to UV light. The authors propose that polyarylates undergo the Photo-Fries rearrangement resuiting in carbonyl and hydroxyl groups ortho to one another,-structurally similar to o-hydroxybenzophenones which are Xnown light absorbers. Thus, the polyarylates have increased photostability in the bulk of the material.
Cohen et al in Transparent Ultraviolet-Barrier Coatings, Journal of Polymer Science, Part A-l, Vol. 9, pages 3263 to 3299 (1971) describe a number of phenyl polyesters, including polyarylates, which were synthesized to furnish molecules whose backbones rearrange under UV light to an o-hydroxybenzophenone structure. This Photo-Fries rearrangement produced ultraviolet opacity in an irradiated f~lm whlle maintaining visual transparency. Thin coatings of these polyesters completely protected substrates ordinarily sensitive to ultraviolet light. The authors state that spectroscopic analysis of various rearranged films and coatings showed that the o-hydroxybenzophenone polymer formed was concentrated at the lrradiated , - , , " ''" ,' ~

.~ , , , - ( 3 - ~3~58 surface of the original polyester coating as a "skin". Such a skin, formed in situ during the irradition, functioned to protect both the original polyes~er costing as well as the coated substrate from degredation by ultraviolet ~rradiation.
Furthermore, a significant "healing" mechanism appeared inherent in the coatings, for as the exposed skin ultimately degraded under sxtended ultraviolet lrrsdiation, more of the underlying polyester layer apparently rearranged to compensate for the loss~ Thus, ~he clear coating functioned both as a protective skin and a rearrangeable reservoir.
U.S. Patent 3,492,261 describes film ~orming solutions of rearrangefible aromatic polyesters which are the polymeric reaction product of an aromatic dihydric compound and an aromatic dicarboxylic compound. It is stated in this patent that the preferred dihydric compounds are the ester derivatives of 4,4-bis(4'-hydroxyphenyl)pentanoic acid. The solutions of aromati~ polyesters can be coated onto a substrate and dried to transparent films? are capable of absorbing ultraviolet ligh~
and undergo rearrangemen~ in the presence thereof to form a transparent compound which is stable to and will act as a barrier to ultraviole~ light.
U.S. Patent 3,503,77~ discloses substrates which are coated with rearrangPable aromatic polyesters which are the polymeric reaction product of an sromatic dihydric compound and an aromatic dicarboxyl compound. The outer exposed surface of the Rromatic polyester coatings rearrange under the .

.

~3~5~g lnfluenc~ of ultraYiolet llght to form a new transpar~n~ compound which i5 stable to and will ~ct ~s a b~rrier to ultr~vlolet li~ht.
U.S. Paten~ 3,444,129 discloses rearrangeable arQmatic polyesters which are the polymeric reaction product of an ~romat~c dihydric compound, ~nd an aromatic dicarboxylic compound.
The preferre~ dihydric compound ls sta~ed to be ~he ester derivatives of 4,4-bis(4'-hydroxyphenyl) pentanoic acid. Yhe re&rran~eable aromatic polyesters are useful a5 ultraviolet light b~rriers.
U.S. P&tent 3,460,961 descrlbes substrates which Are protected with a transparent arom~tic polyester coating of ~wo cont~guous superposed layers. The aromatic polyester compounds are the reactlon product o an aromatic dihydrlc compound and an aromatic dicarboxylic compound. The aromatic polyester coating undergoes rearran8ement in the presence of ultraviolet light to form a tran~parent compound which ls stable to ~nd ac~s ~s a barrier to ultraviolet light.
However, in all of these references coatings are being ut~lized which, as discussed above, require expensive solvent coating equipment and require evapor~tion o ~ solvent.
U~S. Patent Application Serial No. 596,075 filed April 4, 1984 in the n~mes of L.M. R~beson et al, ~ltled "Laminate Compositions With Polyaryl~te ~nd Poly Aryl Ether't, commonly assigned, now U.S~ Patent 4,503,121, issued March 5, 1985, describes laminate compositions comprising a polyarylate, or blends thereof, derived rom a dihydric phenol and an aromatic dicarboxylic acid which is laminated upon the surface of a poly~aryl ether~, particularly .

.

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polysulfol1e. It is st~ted ~herein th~t excellent protection is ~ff~rded the polysulfone ag~inst degradation resulting rom prolonged UV exposure by laminating the polyaryl~te upon its surf~ce.
THE INVENTION
In the present lnvention it h~s been found th~t a shee~ mad~ from an aromatic polycarbon~te or ~ thermoplastic polyester, or combinations of these polymers can be protected from ultraviolet light by laminating thereon a sheet made from R polymer which undergoes a Photo-Fries rearrangement, such as a polyarylate, onto one or both o~ its surfaces. As compared to the prior rt methods which utilize a co~ting to protect a substrate ag~inst UV light, the present invent~on does not have the disadv~ntages of solvent removal. Also, this invention provides permanent protection to the underlying sur~ace as compared to a coating which can wear off.
~- The comb1nation of polyarylate laminated onto polycarbon~te or polyester is un~que since excellent ~dheslon ls observed and scr~p c~n be reused without ~ffecting the tr~nsparency of the lamln~ted product. This allows for a unique ~nd important ch~racterlstic (reuse of scrap) which is the essence of th~s ihvention.

Thus the invention provides in one embodiment a ~ layered article fabricated by coextruding into laminar : contact ~a) a molten polyarylate derived from a dihydric phenol and an aromatic dicarboxylic acid and (b) a molten polymer selected from the group consisting of (i) a thermoplastic aromatic polycarbonate, (ii) a thermoplastis polyester derived from an aliphatic or cycloaliphatic diol, or mixtures thereof, and at least :
.

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one aromatic dicarboxylic acid and (iii) mixtures of the polycarbonate and polyester.
In another embodiment the invention provides a laminate comprising a layer (a) o f p o ly a ry 1 a t e derived from a dihydric phenol and in aromatic dicarboxylic acid, said layer being in laminar contact ~ith a layer (b) of a polymer selected from the group consisting of (i) a t h e rm op 1 a st i c aromatic polycarbonate, (ii) a thermoplastic polyester derived from an aliphatic or cycloaliphatic diol, or mixtures thereof, and at least one aromatic dicarboxylic acid and (iii) mixtures of the polycarbonate and polyester, wherein said layer (b) incorporates polyarylate as defined for use in said layer (a).
In a further aspect of the invention there is provided a process for manufacturing a layered thermoplastic material which comprises: (1) fabricating a layer (a) of polyarylate derived from a dihydric phenol and an aromatic dicarboxylic acid and a layer (b) of a polymer selected from the group consisting of (i) a thermoplastic aromatic polycarbonate, (ii) a thermoplastic polyester derived from an aliphatic or cycloaliphatic diol, or mixtures thereof, and at least one aromatic dicarboxylic acid and (iii) mixtures of the polycarbonate and polyester wherein said layer (b) has blended therein a polyarylate as defined for use in layer (a); (2) laminating the layers together; and (3) reusing a portion of the resulting laminate as raw material for said fabrication of layer (b)o In .another embodiment the invention provides a process for manufacturing a layered article which comprises: (I) laminating together a layer (a) fabricated from polyarylate derived from a dihydric phenol and an aromatic dicarboxylic acid and a layer (b) fabricated from a polymer selected from the group consisting of -5b - 1 315 ~ 5 ~

(i) a thermoplastic aromatic polycarbonate, (ii) a thermoplastic polyester derived from an aliphatic or cycloaliphatic diol, or mixtures thereof, and at least one aromatic dicarboxylic acid, and (iii) mixtures thereof, in combination with polyarylate as defined for use in said layer (a); and (2) recycling a portion the resulting laminate for reuse as a raw material for fabrication of said layer (b).

Specific~lly, the present invention in one aspect compriæes a lamlnate formed from a layer of a polyarylate shee~ ~nd a layer of an aromatic polycarbonate, a thermopl~stic polyes~er, or blends o~ the polycarbons~e and polyester sheet. A
preferred laminate comprises a l~yer of a polyarylate derived from bisphenol-A and isophthallc ~`
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and/or terephthalic acid sheet and a layer of a polycarbonate derived from bisphenol-A and phosgene and/or a polyester such as poly(ethylene terephthalate) sheet. The polyarylate sheet may be laminated to one or both sides of the polycarbonate and/or polyes~er sheet.
The laminstes of ~his inven~ion can be from about 30 mils to about 1/2 inch ~hick, preferably from about 40 to about 90 mils thick. The sheets which form the laminates are from about 1 mil to About 100 mils, preferably from about 2 to about 10 mils thick for ~he polyarylate and from sbout 2 mils to 1/2 inch, preferably from about 50 to about 80 mils thick for the polycarbonate and/or polyester.
Polyarylates The polyarylates which are suitable for use in this invention are derived from a dihydric phenol and at least one aromatic dicarboxylic acid and have a reduced viscosity of from about 0.4 to greater than about 1.0, preferably from about 0.6 to about 0.8 dl/gm, as measured in chloroform (0.5 g/lOOml chloroform) or other suitable solvent at 25C.
A particularly desirable dihydric phenol is of the following formula:

(Y)a (Y)a HO ~ ~ Rl)O-l ~ OH

whereln Y is independently selected from, hydrogen, alkyl groups of 1 to 4 carbon atoms, ehlorine or bromine, each 8, independently, has a value of from p-14841 . .

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: . , : ' 1 3 ~ 8 O to 4, inclusive, and ~1 is a divalent saturated or unsaturated aliph~tic hydrocarbon radical, p~rticularly an alkylene or alkylidene radical having from 1 to 6 carbon atoms, or a cycloalkylidene or cycloalkylene radicals h~ving up to and including 9 carbon atoms~ 0, CO, S02, or S. The dihydric phenols may be used individually or in combination.
The dihydric phenols tha~ may be used in this invention include the following:

2,2-bis-4(4-hydroxyphenyl)propane;
bis-(Z-hydroxyphenyl)methane, bis-(4-hydroxyphenyl)methane, bis-(4-hydroxy-2,6-dimethyl-3-methoxyphenyl) methane, 1,1-bis-(4-hydroxyphenyl)ethane, 1,2-bis-(4-hydroxyphenyl)ethane, 1,1-bis-(4-hydroxy-2-chlorophenyl)ethane, 1,3-bis-(3-methyl-4-hydroxyphenyl~ethane, 1,3-bis-(3-methyl-4-hydroxyphenyl)propane, 2,2-bis-(3-phenyl-4-hydroxyphenyl)propane, 2,2-bis-(3-isopropyl-4-hydroxyphenyl) propane, 2,2-bis-(2-isopropyl-4-hydroxyphenyl) propane, 2,2-bis-(4-hydroxyphenyl)pentane, 3,3-bis-(4-hydroxyphenyl)pentane, ~,2-bis-(4-hydroxyphenyl)heptane, 1,2-bis-(4-hydroxyphenyl)1,2-bis~(phenyl~-propane, 4,4'-(dihydroxyphenyl)ether, 4,4'-(dihydroxyphenyl)sulfide, 4,4'-(dihydroxyphenyl)sulfone, 4,4'-(dihydroxyphenyl)sulfoxide, 4,4'-(dihydroxybenzophenone), and n~phthalene diols The aroma~ic dicarboxylic ac1ds that may be used in this lnvention include terephthalic acid, isophthalic acid, any of the naphthalene dicarboxylic acids ~nd mixtures thereof, as well as alkyl substituted homologs of these carboxylic acids, wherein the alkyl group contains from 1 to about 4 carbon atoms, and acids containing o~her inert substituents, such as halides, alkyl or aryl ethers, ~nd the like. Acetoxybenzoic acid can also be used. Preferably, mixtures of isophthalic and terephthalic ~cids are used. The isophthalic acid to terephthalic acid ratio in the mixture is abou~
0:100 to about 100:0, while the most preferred ~cid ratio is about 75:25 to about 50:50. Also, from about 0.5 to about 20 percent of aliphatic diacids containing from 2 to about 10 carbon atoms, such as adipic acid, sebacic acidj and the like may be additionally used in the polymerization reaction.
The polyarylates of the present invention c~n be prepared by any of the well known prior art polyester forming reactions, such as the reaction of the acid chlorides of the ~romatic dicarboxylic acids with the dihydric phenols; the reaction of the diaryl esters of the aromatic dicarboxylic acids with the dihydric phenols; or the reaction of the aromatic diacids with diester derlvatives of the dihydric phenol. These processes are described in, for example~ U.S. Patents 3,317,464; 3,948,856, 3,780,148; 3,824,213; and 3,133,898~
.

.

1 3 ~ 8 g The polyarylates ~re preferably prepared by the process as set Eorth in U.S. Patent 4,321,355.
This process comprises the following steps:
~ a) reacting an acid anhydride derived from an acld containing from 2 to 8 carbon atoms with at least one dihydric phenol to form the corresponding diester; and (b) reacting said dlester with a~
least one aromatic dicarboxylic acid at a temper~ture sufficient to form the polyarylate, wherein the improvement comprises removing residual acid snhydride after formation of the dihydric phenol diester so that its concentration is less than about lSOO parts per million.
The acid anhydride suitable is derived from an acid containing from 2 to 8 carbon atoms. The preferred acid anhydride is acetic anhydride.
The dihydric phenol is described above.
Gener~lly, the dihydric phenol reacts with the ~cid anhydride under conventional esterification conditions to form the dihydric phenol die ter. The reaction may take place in the presence or absence of a solvent. Additionally, ~he resctlon may be conducted in the presence of a conventional esterification catalyst or in the absence thereof.
Aromatic Pol~carbonate The thermoplastlc aromatic polycarbonates that can be employed herein are homopolymers an~
copolymers and mixtures thereof, which have an intrins~c viscosity of from about 0.4 ~o about l.O
dl./g. as measured in methylene chloride at 25C.
The polycarbonates are prepared by reacting a .
~, .

1 ~ 8 dihydric phenol with a carbonate precursor. Typical of some of ~he dihydric phenols ~hat may ~e employed are bisphenol-A, bls(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4-bis(4-hydroxyphenyl)heptane, 2-?-(3,5,3', 5'tetrabromo-4,4'-dihydroxydiphenyl)propane, (3,3'dichloro-4,4'dihydroxydiphenyl)methane, and the like. Other dihydric phenols of the bisphenol type are described in, for example, U.S. Patents, 2,999,835, 3,028,365 and 3,334,154.
It is, of course, possible to employ two or more different dihydric phenols or a copolymer of a dihydric phenol with a glycol or with hydroxy or acid terminated polyesters.
The carbonate precursor may be either a carbonyl halide, a carbonate ester, or a haloformate. The carbonyl halides which cAn be employed herein are carbonyl bromide, carbonyl chloride and mix~ures thereof. Typical of the carbonate esters which may be employed herein are diphenyl carbonate, di-(halophenyl)carbonates, such as di-(chlorophenyl)carbonate or di-(bromophenyl)carbonate, eec., di-(alkylphenyl)carbonates such as di(tolyl)carbonate, di(naphthyl)carbonate, di(chloronaphthyl)carbonate, etc. or mixtures thereof. The haloformates suitable for use here1n include bis-haloformate of dihydric phenols for example, bischloroformates of b1sphenol-A, of hydroqulnone, etc. or glycols for example, bishaloformates of ethylene glycol, neopentyl glycol, polyethylene glycol, eec~ While other ~, ~ D-14841 :

~315~5~

c~rbonate precursors will be ~pparent to those skilled in the art, carbonyl chlorlde, also known as phosgene, is preferred.
The aromatic polycarbonate polymers may be prepared by methods well known in the art by using phos~ene or a halo~ormate and by employing a molecular weight regulator, an acid accep~or ~nd a catalyst. The molecular weight regulators which can be employed in carrying out the process include monohy~ric phenols, such as phenol, para-tert~ary-butylphenol, para-bromophenol, primary and secondary amines, etc. Preferably, a phenol is employed as the molecular weight regulator.
A suitable acid acceptor may be either an organic or an inor~anic acid acceptor. A suitable organic acid acceptor is a tPrtiary amine and includes materials, such as pyridine, triethylamine, dimethylsniline, tributylamine, etc. The inorganic acid acceptor may be one which can be either a hydroxide, a carbonate, a bic~rbonate, or ~
phosphate of an alkali or alkaline earth metal.
The catalysts which are employed herein can be ~ny of the suitable c~talysts that aid the polymerization of, for example, bisphenol-A with phosgene. Suitable cztalysts include tertiary amines, such as triethylamine, tripropylamine, N,N-dimethylaniline, quaternary ammonium compounds, such as tetrae~hylammonium bromide, cetyl triethyl ammonium bromide, tetra-n-heptylammonium ~odide, and quaternary phosphonium compounds, such RS
n-butyltriphenyl-phosphonium bromide and methy.l-triphenyl phosphonium bromide.

. . ..

~31~g The polycarbonates can be prepared in a one-phase (homogensous solution) or a two-phase (interfacial) systems when phosgene, or a haloformate are used. Bulk reactions are possible when the diarylcarbonate precursors are used.
Also, aroma~ic polyes~er carbonates may be used. These are described in, for example, U.S.
Patent 3,169,121. The preferred polyester carbonate results from the condensation of phosgPne, terephthaloyl chloride, isophthaloyl chloride with bisphenol-A and a small amount of p-tertbutylphenol.
PolYesters The polyesters which are suitable for use herein are derived from an aliphatic or cyloaliphatic diol, or mixtures thereof, containing from 2 to abou~ 10 carbon atoms and at least one aromatic dicarboxylic acid. The polyesters which are derived from an aliphatic diol and an aromatic dicarboxylic acid h~ve repeating units of the following general formula:

O O

~O-~CH23-- OC~ C~3_ wherein n is an integer of from 2 to 10.
The pre~erred polyester is poly(ethylene terephthal~te).
Also contemplated herein sre the ~bove polyesters with minor ~mounts, e.g., from 0.5 to about 2 percent by weight, of units derived from - - . :, , . ~ .

- ~3~g~8 ~lipha~ic acids and/or aliphatic polyols, to form copolyesters. The ~liphatic polyols include glycols, such as poly(ethylene glycol~. These can be made following the teachings of, ~or example, U.S. Patents 2,465,319 and 3,047,539.
The polyesters which are derived from a cycloaliphatic diol ~nd an aromatic dicarboxylic acid are prepared by condensing either ~he cis - or trans-isomer ~or mixtures thereof) of, for example, 1,4-cyclohexanedimethanol with an aromatic dicarboxylic acid so as to produce a polyester having recurring units of the follow~ng formula:
f CH2~H2 (I) ~ O-CH2C ~ \ CB-CH2-O-C-R2 -C
C82-ch2 wherein the cyclohexane ring is selected from the cis- and tr~ns- isomers thereof and R2 represents ~ an aryl radical containing 6 to 20 carbon atoms and which is the decarboxylated residue derived from an aromatic dicarboxylic ac~d.
Examples of aromatic dicarboxylic acids . indicated by R2 in formula I, are isophthalic or terephthalic acid, 1,2-di(p-carboxyphenyl)ethane, 4,4'-dicarboxydiphenyl ether, etc., and mixtures of these~ All of these acids contain at least one ~ aromatic nucleus. Fused rings can also be present, such as in 1,4-or 195-naphthalenedicflrboxylic acids. The preferred dicarboxylic acids ~re terephthalic acid or ~ mixture of terephthalic and isophthalic acids.

' ` -:

~3~5~

A preferred polyester may be derived from the reaction of elther ~he cis-or trans-lsomer (or a mixture thereof) of 1,4-cyclohexanedlmethanol with a mixture of isophthalic and terephthalic acids.
These polyesters have repeating units of ~he formula:

(II) -O-CH2CH CH2-CH2 \ CH CH2 C ~ C -CH2-CH;~

Another preferred polyester is a copolyester derived from a cyclohexane dimethanol, an alkylene glycol and an aromatic dicarboxyllc acid. These copolyesters are prepared by condensing either the cis- or trans-isomer (or mixtures thereof) of, for example, l,4-cyclohexanedimethanol and an alkylene glycol with an aromatic dicarboxylic acid so as to produce a copolyester having repeating units of the ~ollowing formula:
O O
~CR 2 C ;! ~
t CH2 c~2 CH~CH20_C_~ ~

o o . ~ 11 11 ~
~- (CH2)n-0C R2 t b `
.

' :, ~ . -~ ~ ' 1 3 ~ 8 wherein the cyclohexane ring is sel~cted from the cis- and trans- isomers thereof, R2 is as previously defined, n is an integer of 2 to 10, the b units comprise from about 10 to about 90 percent by weight and the c units comprise from about lO to about 90 percent by weight.
The preferred copolyester may.be derived from the reaction of either the Ci5- or trans-isomer (or mixtures thereof) of I,4-cyclohexanedimethanol ~nd ethylene glycol with terephthalic acid in a molar ratio of 1:2:3. These copolyesters have repeating units of the following formula:

~ CH2 C112~
(VI) ~ OCH2CH \ ~H~H2-0-C- ~ - t ~ CH2 C~
d ~ O~CH2~0C~C ~ .

wherein d can be 10 to 10,000. BlocX as well as random copolymers are possible.
The polyester as described herein are either commercially available or can be prod~ced by methods well known ln the art, such as those set forth in, for example, U.S. Patent 2,901,466.
The polyesters used herein have an intrinsic viscosity of from about 0.4 to about 2.0 dl/g. as measured in 8 60:40 phenolltetrachloro-ethane mixture or similar solvent at 23 to 30~C.
The polyarylate may be blended with other polymers includ~ng polycarbonates and/or .

- ~ ( polyesters. The polycarbonate and/or polyester may be blended with each other or with other polymers such as a polyarylate. Other additives may be used with ~he pclymers such as seabilizers~ flame retardants, and the like. Since the primary use of the laminate is or glazing applications which are tr~nsparent, only those additives are generally used which maintain the transparency of the laminate.
However, i~ an application is desired where transparency is not needed, such as certain types of solar collectors, than any desired additive may be used.
The thermoplastic polymer, and one or more optional additives are generally compounded in an extruder. The cGmpounding is carried out at temperature of from about 200C to about 400C. The compounded material may be pelletized by conventional techniques. The compounded material is extruded lnto a sheet and then formed into a laminate.
Alternatively, the thermoplastic polymer either alone or in combination with other materials may be fed in particulate form (such as pellets, granules, particles, powders, and the like) into an extruder which extrudes the material into a laminate. The extruders which are used to form the laminate are well known ln the art. Typically, thP
extruder may be a 2 l/2 inch Davis Standard extruder containing an extruder screw with a length to diameter ratio of 24 to l.
The laminate may be prepared by the procedure and uslng the apparatus as described in :
.

- 17 - ~3~5~8 U.S. Patent 3,557,265. In the method of said patent, film or shee~ having a plurality of layers is formed by deform~ng a flowing stream having layers of diverse thermoplastic material wherein the cross-sectional con~iguration of the plurality of flowing streams is altered by reducing the dimension of the stream in a direction generally perpendicular to the interfaces between the individual streams and by increasing the dimension of the stream in a direction generally parallel to the interface to provide a sheet havlng a laminar structure.
In another method two or more previously extruded sheets are brought together under pressure and ~emperature conditions or in the presence of adhesives in order to obtain adherenc2 of the sheets to one another.
Coextrusion offers the least expensive means of preparing the laminate. Within coextrusion, three di~ferent techniques are most often employed. In one of these tschniques, two or more sheets are extrude~ from separate extruders through separate sheet dies into contact with one another while still hot and then passed through a single set of rollers or another extrusion die and down a single sheet line. Another coextrusion technique employs an adaptor or other means of bringin8 two or more different plastic materials from two or more extruders into contact with one another prior to their passage through an extrusion die. A further coextrus~on technique is where two or more polymer melts meet in an extrusion die to form ~ laminate. Coextrusion is the preferred :

D-14e41 , " ~ , .', .
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technique for forming the lsminates of this invention.
The laminate may be ~ormed into a shaped article such as a lens, a globe, and the like. If the laminate is to be used as a window, ~he lam~nate may be coated with a mar resistant coating.
EXAMPLES
. The following examples serve to give specific illustrations of the practice of this invention but they are not intended in any way to limit the scope of this invention.
The following designations used in the Examples have the following meaning:
.
YhEY~ A polymer having repeat units of the formula:
O

having a reduced viscosity of 0.66 as measured in p-chlorophenol, 0.2 gllOO ml at l ~ 49C (ARDEL~ D-100 obta1ned '~ from Union Carbide Corp.) PolyarYlate TI A blend of 60 weight percent of Polyarylate I and 40 weight ~: - percent of a poly(ethylene :
~ D-14841 .

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- 19 - ~31~8 rephthalate) h~ving an in~rinslc viscosity of 0.64 as measured in 60:40 phenol/tetrachloroethane at 23C.
Polycarbonate I: An aromatic bisphenol -A
polyc~rbonate havlng a reduced viscosity of 0.64 dl/g as measured in chloroform at 25C.
(Lexan 101 sold by General Electric Co.) Polycarbonate II- An aromatic bisphenol -A
polycarbonate (Lexan 143 sold by General Electric Co. ) PolYcarbonate III: An aromatic bisphenol -A
polycarbonate (Lexan 153 sold by General Electric Co. ) The samples were tested according to the following procedures:

Test ASTM Desi~na~ion Specular Gloss ~-2457 Light Transmission D-1003-61 H~ze D-1003-61 Color Factor ~ellowness Index D-1925-70 Dominant Wavelength Purity D-791 A brief description of these tests is the fol~owing:
SPecul~r Gloss ~ -Speeular gloss values are used to comp~re .

.
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- 2~ -the shiny appearance of surfaces and generally are related to surface smoothness. Th~ speclflc definition is the relative luminous fractional reflectance of a specimen at the specular direction (where the rela~iYe luminous fractional reflectance is the ratio of the luminous flux reflected from, to that incident on, a specimen for specified solid angles).
Li~ht Transmission Light transmission is defined as the ratio of the transmitted to the incident li~ht.
Haze The haze of a material is defined as that percenta~e of transmitted light which when passing through the specimen deviates from the incident beam by forward scattering (deviation > 2.5 degrees).
Color Factor Color f~ctor is defined as the purity of color, in percent, divided by the thickness, in inches, of the test specimen.
Yellowness Index Yellowness is defined as the deviation in chroma from whiteness in the dominant wavelength range from 570 to 580 m.
Dominant Wavelen~th The dominant wavelength o$ a color is the wavelength of the spectrum color that when additively mixed in suitable proportions with a specified achromatic color, yields a match with the color desired.

1 31~658 Accelerated weathering of the test specimens was conducted in the following exposure units:
.
ASTM Test Method Name G-23 Fade-Ometer XW-weathering (carbon ~rc) Xenon Controls A to E
Polyarylates I and II and Polycarbonates I
to III were compression molded into test specimens 1/8 x 4 x 4 inches.~ The samples were exposed for 8000 hours in the XW-weatherometer (Table I), a Fadeometer (Table II) and a Xenon Lamp (Table III).
The results ere shown in Tables I to III.

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2Z ~L 3 ~ 8 = c ~

-t n, o ~ ~

C ~ n ~ 3 O
O ~ ' - o e g ~n ~ w ~ _ ~V .
ow~

~ N Yl Ul ~ a~ ~ ~ ~3 (;~ ~
w ~ w ~ C = ~

O. a~n ~ 5 W CD o ~ ~ ~ ~ r O W -- W ~ W ~

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The data in Tables I to ~II shows that the poly~rylate samples exhibit less change in ~he three acceler~ed weathering tests than the polycarbonate samples. o~ the three accelerated weathering tests, the F~deometer yields the closest result between polyc~rbonate and polyaryl~te. Polyaryla~e still exhiblts advantages in higher gloss, lower haze, and lower light transmission changes versus the polycarbonate samples. Wi~h exposure to the XW-Weatherometer, the polyarylate samples also exhiblt much better retention of gloss, much lower haze, and better retention of light transmission ~versus initial values). The polyarylate samples exhibit ~ slightly lower change in color factor and ~ yellowness index than all the polycarbonate samples.
1 Polyarylate II exhibits better overall characteristics than ~he stabilized polycarbonate products (Lexan 143, Lexan 153).
The sudden increase in haze for both Lexan j lOl and Lexan 153 demonstrates a serious deficiency of polycarbonate (even the UV stabilized version, Lexan 153) for exterior transparent applications.
The increase in haze is accompanied by a methodic~l decrease in light transmission and impact strength.
The haze ls micro cracking of the surface and this reduces the impact resistance of the sheet. It also results ~n loss of gloss imparting a dull appea-rance to the surface.
Polyarylate I and Polycarbonate III (UV
plus heat stabilized polycarbonate) were in~ection -molded into ASTM test parts on ~ 3 oz. molding m~chine. Included were tensile bars (l/8 in.), flex .

:-131~
- 2~ -bars (1/8 in. and 114 in. thick) snd plaques ~1/8 in.~.
All samples were exposed in an XW-Weatherometer in accordance with ASTM-G-~3 (XW
carbon arc, 18 min. water sprary every two hours) for up to 8,000 hours total exposure.
The samples were tested for tensile modulus according to ~STM D-638 yield strength and yield elongation according ~o ASTM D-638 and break elongation according to ASTM D-638.

. ~

,.

- 2 7 - ~31~8 TABLE !V
EFFECT OF XW-~EATHEROMETER ON TENSILE P~OPERTIES

Tensile Yi~ld Yi~ld Break Sarple Time Modulus Strength Elongotion Elongation (hr) ~k Psi? (psi) (S) Polyarylate I O Z69 9,710 9.1 58.5 I,ooo 315 9.730 8.5 27.5 2,U00 276 9,~30 9.2 36.0 4,000 ~10 9,870 9.6 22.5 , 8,000 524 9,870 8.4 16.5 i Polycarbcnate 111 0 306 ~,940 6.4 121.0 7 , .ooo ~5~ 8,g20 5.6 ~1.0 2,000 311 9,160 6.2 92.0 4,G00 ~57 9,140 5.5 B4.5 a,ooo ~66 9,310 5.3 ~3.0 ..

.. ~. .

- 28 ~ g ~8 Table V shows the effect of exposure of Polyarylate I and Polycarbonate III on tensile impAct, (measured according to ASTM D-1822) notched Izod impact (measured according to ASTM D-256), and heat ~istortion temperature (measured ~ccording to ASTM D-~35~.
~ omparing tensile impact values, ~he polyarylate was as tough as the polycarbonate after 8,000 hours exposure. Loss of toughness as a percent of unexposed toughness was much less for the polyarylate slnce the polycarbonate has a much higher st~rting value. In notched Izod toughness, the polycarbonat~ lost over 90 percent of its original value after only 2,000 hours exposure while the polyarylate showed only slight loss in Izod impact after 8,000 hours.

~ O
.

13~ $ 6 33 TABLE V
EFFECT OF XW-~EATHEROMETER ON I MPACT
AND HEAT DEFLECT I ON TEMP~RATURE
T;n~ TenS; IQ ImPACt NotChed IZOd HDT
S~fnPIe _ lhrs) (ft-lb7in ) tft-lb/in ) (C~

PolyarylateI 0 119 3.8 174 - I ,t~O ~.7 165 2 ,000 68 ~.5 168 4,000 77 ~.0 166 8,000 71 2.5 160 PolycarLonate 111 0 275 i8 133 I, 000 -- 7 . 5 1 34 2,~00 84 1.7 135 0 105 1.7 133 3,000 31 1,6 131 `

`' `

., -, - 30 - ~ 31~ ~ 3~

Table YI shows the effect o~ exposure on optical properties of Polyarylate I and Polycarbonate III.
Light transmission of polycarbonate was not affected by the exposure, while polyarylate ~howed slight change. Most signif$can~ W8S the comparison of haze development in the resins. The polycarbonate rapidly developed a very frosted surface, like etched glass, after less than 2,000 hours exposure, whlle the polyaryl~te showed only very light frosting and small increases in haze.
This natural resistance to haze development is advantageous for economic production of outdoor weathering molded parts and sheeting without an additional protective coating.

` D-14841 : .

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.

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- 31 - ~ 5~

TABLE VI
EFFECT OF XW-WEATHEROMETER ON IMPACT
EXPOSURE ON OPTICAL PROPERTIES
Time Tran~mission Haze SsmPle (hrs) _ ~%) t~) Polyarylate I 0 65 6.1 1,000 65 6.3 2,000 63 13.0 4,000 62 13.3 8, 000 58l 5 . 0 Polycarbonste I I I 0 85 l . 3 l / ~0 0 8 3 - -2, 000 . 8387 . 8 4, 000 8670 . l 8, ~00 ~583 . 0 . . -~ ., .
.

- 32 ~ 8 Example A Mylar, i.e., poly(ethylene terephthsl~te), ~ilm having a thickness of three mils was subjected to accelerated testing (carbon arc XW-Weatherometer exposure) as i5, and with 2 mil and 5 mil polyarylate film placed on top of each specimen during exposure. The pendulum impact strength results are listed in Table VII after exposure intervals. The results clearly demonstrate the capability of thin polyarylate films to ~ct as a UV protective coating.
TABLE VII

~. POLYARYLATE FILM EVALUATIO~ AS A UV PROTECTIVE_COATING
: ~ 3 Myl~r Substrste Pendulum ImPact Stren&~ (ft-lb/in ~
XW Exposure Control Mylar Mylar under Mylar under (hours) 2-mil 5-mil Poly- Poly-arylate I arylate I

~ >1,888 >1,880 >1,880 500 10 >1,790 >1,823 l,000 0 1,906 1,652 i~

. .

.,

Claims (27)

1. A layered article fabricated by coextruding into laminar contact (a) a molten polyarylate derived from a dihydric phenol and an aromatic dicarboxylic acid and (b) a molten polymer selected from the group consisting of (i) a thermoplastic aromatic polycarbonate, (ii) a thermoplastic polyester derived from an aliphatic or cycloaliphatic diol, or mixtures thereof, and at least one aromatic dicarboxylic acid and (iii) mixtures of the polycarbonate and polyester.

2. A laminate comprising a layer (a) of polyarylate derived from a dihydric phenol and in aromatic dicarboxylic acid, said layer being in laminar contact with a layer (b) of a polymer selected from the group consisting of (i) a thermoplastic aromatic polycarbonate, (ii) a thermoplastic polyester derived from an aliphatic or cycloaliphatic diol, or mixtures thereof, and at least one aromatic dicarboxylic acid and (iii) mixtures of the polycarbonate and polyester, wherein said layer (b) incorporates polyarylate as defined for use in said layer (a).

3. A process for manufacturing a layered thermoplastic material which comprises:
(1) fabricating a layer (a) of polyarylate derived from a dihydric phenol and an aromatic dicarboxylic acid and a layer (b) of a polymer selected from the group consisting of (i) a thermoplastic aromatic polycarbonate, (ii) a thermoplastic polyester derived from an aliphatic or cycloaliphatic diol, or mixtures thereof, and at least one aromatic dicarboxylic acid and (iii) mixtures of the polycarbonate and polyester wherein said layer (b) has blended therein a polyarylate as defined for use in layer (a);

(2) laminating the layers together; and (3) reusing a portion of the resulting laminate as raw material for said fabrication of layer (b).

4. A laminate as defined in claim 1 or claim 2 which is from about 3 mils to about 1/2 inch thick.

5. A laminate as defined in claim 1 or claim 2 which is from about 40 mils to about 90 mils thick.

6. A laminate as defined in claim 1 or claim 2 wherein the dihydric phenol is of the following formula:

wherein Y is independently selected from, hydrogen, alkyl groups of 1 to 4 carbon atoms, chlorine or bromine, each a, independently,has a value of from 0 to 4, inclusive, and R1 is a divalent saturated or unsaturated aliphatic hydrocarbon radical having from 1 to 6 carbon atoms, or a cycloalkylidene or cycloalkylene radicals having up to and including 9 carbon atoms, O, CO, SO2, or S.

7. A laminate as defined in claim 1 or claim 2 wherein the aromatic dicarboxylic acid is selected from terephthalic acid, isophthalic acid, or mixtures thereof.

8. A laminate as defined in claim 1 or claim 2 wherein the dihydric phenol is bisphenol -A and the aromatic dicarboxylic acid is selected from terephthalic acid, isophthalic acid, or mixtures thereof.

9. A laminate as defined in claim 1 or claim 2 wherein the polyarylate is derived from a mixture of bisphenol-A and hydroquinone and a dicarboxylic acid selected from terephthalic acid, isophthalic acid, or mixtures thereof.

10. A laminate as defined in claim 1 or claim 2 wherein the polyarylate is a polyarylate carbonate.

11. A laminate as defined in claim 1 or claim 2 wherein the aromatic polycarbonate is derived from a dihydric phenol and a carbonate precursor.

12. A laminate as defined in claim 11 wherein the dihydric phenol is bisphenol-A.

13. A laminate as defined in claim 11 wherein the aromatic polycarbonate is derived from bisphenol-A and phosgene.

14. A laminate as defined in claim 11 wherein the polycarbonate is a polyester carbonate.

15. A laminate as defined in claim 1 or claim 2 wherein the polyester has repeating units of the formula:
wherein n is an integer of from 2 to 10.

16. A laminate as defined in claim 1 or claim 2 wherein the polyester is poly(ethylene terephthalate).

17. A laminate as defined in claim 1 wherein the polyester has recurring units of the formula:

(II) wherein the cyclohexane ring is selected from the cis- and trans- isomers thereof and R17 represents an aryl radical containing 6 to 20 carbon atoms and which is the decarboxylated residue derived from an aromatic dicarboxylic acid.

18. A laminate as defined in claim 1 or claim 2 wherein the polyester has recurring units of the formula:

(III)

19. A laminate as defined in claim 1 or claim 2 wherein the polyarylate is blended with polycarbonate and/or a polyester.

20. A laminate as defined in claim 1 or claim 2 wherein the polyarylate is blended with a poly(ethylene terepthalate).

21. A laminate as defined in claim 1 or claim 2 wherein the polycarbonate and/or polyester is blended with a polyarylate.

22. A laminate comprising a sheet made from a layer of a polymer which undergoes Photo-Fries rearrangement and a sheet made from a layer of an aromatic polycarbonate, a thermoplastic polyester, or mixtures of the polycarbonate and polyester.

23. A laminate as defined in claim 22 wherein the polymer which undergoes the Photo-Fries rearrangement is a polyarylate.

24. A shaped article made from the laminate of claim 1.or claim 2.

25. A shaped article as defined in claim

26 in the form of a lens.

26. A shaped article as defined in claim 26 in the form of a globe.

27. A laminate as defined in claim 1 or claim 2 costed with a mar resistance coating.