DE2348838A1 - Fire-resistant polyurethanes for furnishing foam and insulation - contg. isocyanurate gps. and melamine as flame retardant - Google Patents

Abstract

Polyurethanes contg. isocyanurate gps. are made from mixts. of polyisocyanates, catalysts and 2.5-50 (10-30) wt. % melamine, based on the total compsn., opt. with polyols, blowing agents and other usual additives. Mfr. of coatings or pref. (semi-)rigid foams with the pores, for use as upholstery or insulating materials, requires smaller quantity of melamine than for halogenated alkyl phosphate flame retardants, and the instability of polyol/phosphate ester mixts. is avoided. The melamine is dissolved or suspended at 0-100 degrees (15-60) degrees C in the polyol, polyol/polyisocyanate mixt. or pref. in the polyisocyanate; the other ingredients being incorporated at 0-100 degrees C and the mixt. allowed to foam.

Description

Our reference: O.Z. 0190/02006 M / Wil 2844 Lemförde, September 26th, 1973

Process for the production of flame-resistant polyurethane plastics containing isocyanurate groups

The invention relates to a process for the production of flame-resistant polyurethane plastics containing isocyanurate groups, the flame resistance is improved by adding melamine.

The production of isocyanurate-containing polyurethane foams is known. Here, polyisocyanates are usually used in the presence of auxiliaries and catalysts cyclized and polymerized, and the isocyanurates and polymers obtained containing isocyanate groups are reacted with polyols. If necessary, it is also appropriate to use the tri or To carry out the polymerization reaction and the polyol addition at the same time. Such Polymerschaumstoffβ have a high temperature resistance, but only a relatively low flame resistance

It has therefore been proposed to incorporate flame retardants, such as tris-2-chloroethyl phosphate and tris-chloropropyl phosphate, into polyurethane foams containing isocyanurate rings. The disadvantage here is that such flame retardants must be used in large amounts, for example in amounts of up to 300 Qew. #, Based on the polyol component, in order to to achieve sufficient effects. Another disadvantage is that mixtures of halogenated alkyl phosphates, polyols and optionally other auxiliaries have only limited storage stability. This instability manifests itself in the formation of crystalline deposits and in changes in the reactivity.

The invention was based on the object of eliminating these Naohteile and the flame resistance of isocyanurate-containing polyurethane plastics by adding an inexpensive one To improve the substance.

OI9O / T23 / ^72/2

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The present invention thus relates to a process for the production of waterproof polyurethane plastics containing isocyanurate groups from polyisocyanates, catalysts and optionally polyols, blowing agents and auxiliaries, which is characterized in that the polyurethane plastics 2.5 to 50 0ew. # Melamine, based on the total weight, incorporated as a flame retardant.

Organic isocyanates with a functionality of at least two are suitable for producing the flame-resistant, isocyanurate-containing polyurethane plastics according to the invention. Examples include aromatic polyisocyanates such as diphenylmethane diisocyanate, triphenylmethane triisocyanate, biphenyl diisocyanate, m- or p-phenylene diisocyanate and 1,5-naphthylene diisocyanate. The crude and pure toluene diisocyanates and mixtures of 2,2'-, 2, V- and 4.4 ^t -diphenylmethane diisooyanate and polyphenyl polymethylene polylsooyanates are preferably used. The polyisocyanates can be used individually or as mixtures.

Catalysts for the cyclization and polymerization of isocyanates are known. Examples are selenium: strong bases, such as quaternary ammonium hydroxides, for example benzyltrimethylammonium hydroxide; Alkali metal hydroxides, for example Sodium or potassium hydroxide; Alkali metal alkoxides such as sodium methylate and potassium isopropylate; Trlalkylphosphine, for example triethylphosphine; Alkylaminoalkylphenols, for example 2,4,6-tris- (dieethyla «inotnethyl) -phenol; 3- and / or 4-substituted pyridines, for example 3- or 4-methylpyridine; organometallic salts, for example tetrakis (hydroxyethyl) sodium borate; Friedel-Crafts catalysts, for example Aluminum chloride, ferric chloride, boron fluoride and zinc chloride, and alkali metal salts of weak organic acids and nitrophenolates, for example potassium octoate, potassium 2-ethylhexoate, potassium benzoate, sodium picrate and phthalimide-potassium. In many cases it is advantageous, in addition to the cyclization and polymerization catalysts mentioned, to additionally use compounds that promote polyurethane formation

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ORIGINAL INFE

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catalyze from polyols and polyisocyanates. Are suitable for example tertiary amines such as 1,4-diazabicyclo- (2,2,2) -octane and N, N-dimethylbenzylamine, certain organic metal compounds such as stannous octoate and dibutyltin laurate and mixtures of tertiary amines and tin compounds

The appropriate amount of catalyst to make those of the present invention Polyurethane plastics depend on the effectiveness of the catalyst in question. In general it has proven to be advantageous to use 1 to 15 parts by weight, preferably 2 to 12 parts by weight of catalyst for Use 100 parts by weight of organic polyisocyanate in each case.

To propellants which are used in the process according to the invention water, which reacts with isocyanate groups to form carbon dioxide. The amounts of water which can be conveniently used are from 0.1 to 2 pounds based on the weight of polyisocyanates, if appropriate Larger amounts of water can also be used, but preferably not if the thermal stability or the thermal insulation properties are of particular importance.

Other blowing agents that can be used are low-boiling liquids which evaporate under the influence of the exothermic polymerization reaction. Suitable are liquids which are inert toward the organic Polyisooyanat and boiling points of not exceeding 100 ⁰ C at atmospheric pressure, preferably between -40 and + 5O ⁰ C, have. Examples of such liquids are halogenated hydrocarbons, such as methylene chloride, trichlorofluoromethane, dichloro-dlfluoromethane, dichloro-monofluoromethane, dichloro-tetrafluoroethane and 1,1,2-trichloro-1,2,2-trifluoroethane. Mixtures of these low-boiling liquids with one another and / or with other substituted or unsubstituted hydrocarbons can also be used.

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The most expedient amount of low-boiling liquid for the production of semi-rigid and rigid foams depends on the foam density that you want to achieve and, if necessary, on the use of water. In general, amounts of 5 to 40% by weight , based on 100 parts by weight of organic polyisocyanate, give satisfactory results.

Auxiliaries can also be incorporated into the reaction mixture. Called selenium, for example, surface-active substances that support the homogenization of the Starting materials are used and, if appropriate, are also suitable for regulating the cell structure of the foams. Into consideration come siloxane-oxyalkylene mill polymers and other organopolysiloxanes, oxethylated alkylphenols, oxethylated fatty alcohols, paraffin oils, castor oil or ricinoleic acid-sulfuric acid esters and turquoise-red oil.

It can also be advantageous to include a plasticizer in the reaction mixture, so that the tendency to become brittle is reduced in the products. Conventional plasticizing agents can be used, but it is particularly useful to use agents containing phosphorus and / or Contain halogen atoms and thereby increase the flame resistance of the polyurethane plastics. To such Remedies include tricresyl phosphate, tris-2-chloroethyl phosphate, Tris-chloropropyl phosphate and tris-2,2-dibrorapropyl phosphate.

An essential feature of the process according to the invention for the production of flame-resistant polyurethane plastics containing isocyanurate groups is the addition of 2.5 to 50% by weight, preferably 10 to 30% by weight, of melamine, based on the total weight of the polyurethane plastic, as a flaarazo coat. The melamine can be added to the reaction mixture in substance, in the form of a solution and preferably suspended in the polyol and / or preferably incorporated in the polyisocyanate component.

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23A8838

The flame-retardant polyurethane plastics containing isocyanurate groups can be produced without the addition of polyols However, polyols are preferably also used for the production of the polyurethane plastics according to the invention. The polyols and polyisocyanates are expediently used in one Amount reacted so that the ratio of isocyanate to hydroxyl groups is at least 2: 1, preferably between 2 t is 1 and 10: 1.

Polyols which can optionally be used for the production of the polyurethane plastics according to the invention are z. B. monomeric polyols such as ethylene glycol, propylene glycol, tetramethylene glycol, trimethylolpropane, glycerol, pentaerythritol and also polyols with higher molecular weight, which are preferably used, such as polyether and polyesterols

Suitable polyetherols can be prepared by adding one or more alkylene oxides having 2 to 4 carbon atoms in the alkylene radical with a starter molecule which has several contains bonded active hydrogen atoms, converts · Suitable Alkylene oxides are e.g. B. ethylene oxide, 1,2-propylene oxide, IpI-chlorohydrin, 1,2- and 2,3-butylene oxide. The alkylene oxides can can be used individually, alternately one after the other or as mixtures. As starter molecules, for example Consideration: water; Amines, such as ammonia, hydrazine, ethylenediamine, hexamethylenediamine, toluylenediamine, diamino-diphenylmethane and melamine; Amino alcohols such as mono- and diethanolamine; Polycarboxylic acids such as adipic acid and terephthalic acid and polyhydroxy compounds such as ethylene glycol, propylene glycol, Diethylene glycol, glycerine, trimethylolpropane, pentaerythritol, sorbitol and sucrose. The polyalkylene ethers, straight-chain, can be partially branched or branched, have molecular weights from 300 to 10,000, preferably from 400 to 3000, and hydroxyl numbers from 30 to 800, preferably from 35 to 400.

Suitable polyester polyols can be prepared, for example, from dicarboxylic acids and polyhydric alcohols. Dicarboxylic acids are, for example, aliphatic Dicarboxylic acids, such as succinic acid, glutaric acid, adipic acid,

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Suberic acid, azelaic acid and sebacic acid, and aromatic Dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid. The acids can be used individually or as a mixture will. To prepare the polyesterols, it may be advantageous to use the corresponding carboxylic acids instead of the carboxylic acids To use carboxylic acid derivatives, such as carboxylic acid esters with 1 to 4 carbon atoms in the alcohol radical, carboxylic acid anhydrides or carboxylic acid chlorides. Examples of polyhydric alcohols are glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 2,2-dimethylpropanediol-1,3 and 2,2,4-trimethylpentanediol-1,5, triols, such as Glycerin and trimethylolpropane and polyols such as pentaerythritol, sorbitol and sucrose. Depending on the properties you want the polyols can be used alone or as mixtures in various amounts. The polyester polyols, the straight or can be branched-chain, dl- or polyfunctional, have molecular weights from 800 to 4000, preferably from 1000 to 2500 and hydroxyl numbers from 50 to 500, preferably from 60 to 200. Particularly suitable for the production of hard foams containing isocyanurate groups with excellent Polyester polyols with hydroxyl numbers are high temperature and flame resistance with minimal brittleness from 60 to 200 and not more than 1.5 branch points for every 1000 molecular weight units

The polyurethane plastics according to the invention are produced in detail in the following manner. The melamine is dissolved or preferably suspended in the polyol, a mixture of polyol and polyisocyanate and / or preferably in the polyisocyanate at temperatures from 0 to 100 ^° C., preferably from 15 to 60 ^{° C..} Thereafter, this reaction mixture, the other starting materials and, optionally, auxiliaries at temperatures of 0 to 100 ⁰ C incorporated. The reaction mixture is then optionally allowed to foam up.

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According to the method according to the invention, for example Coating agents and preferably semi-rigid and rigid polyurethane foams are produced. The flame-resistant foams containing isocyanurate groups are fine-celled and are preferred used as padding and insulating material.

The parts mentioned in the examples are parts by weight. example 1 To a suspension out

100.0 parts of a mixture of Dilsocyanato-dlphenylmethan and polyphenyl polyraethylen polyisocyanate having an NCO content of 30 to 32 wt.% And 10.0 parts of melamine are added under stirring at room temperature a mix of

10.0 parts of tris (dimethylaminomethyl) phenol, 10.0 parts of monofluorotrichlarmethane and 1.5 parts of a silicone-based foam stabilizer

(DC 190 from Dow Gorning Corp., Midland, Michigan). After a dwell time of 35 seconds, the reaction mixture begins to foam. After a rise time of 5 minutes, a thin-celled, brittle rigid foam with a Extinguishing time from 0 to 1 seconds

To test the flame resistance, hard samples are used the size 20 χ 5 x 2 cm with a Bunsen burner flame of approx. 1060 ° C for 10 seconds so flamed that the tip of the blue flame cone touches the surface of the foam body, and after removing the ignition source, the release time is measured. To measure the thermal stability, rigid foam cubes with an edge length of 5 cm are placed in a Temperature test cabinet with circulating air during a given tent exposed to a certain temperature.

Comparative example la

If a rigid foam is produced analogously to the information in Example 1, but without the addition of melamine, one obtains

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a product that has an extinguishing time of 7 seconds.

Example 2

To a suspension out

100.0 parts of a mixture of diisoeyanato-diphenylmethane and polyphenylpolymethylene-polyisooyanate with an NCO content of 30 to 32 wt. $>,

7.5 parts of an adipic acid-diafciiylene glycol-trimethylolpropane polyester with a molecular weight of 2000 and a hydroxyl number of 60-3 "and 30.0 parts of melamine are added with stirring at room temperature

a mix of

7 # 5 parts TrIs- (disHethylaminometfeyl) -phenol, 15 # 0 parts monofluorotriohloraethane and 1.0 part of a silicone-based foam stabilizer (the

Dow Corning Corp., Midland, Michigan). After a dwell time of 3 seconds, the reaction mixture begins to foam. Di® climbing time is 15 minutes. The result is a foam having a tree weight of 48.2 g / represents a Verlöschzeit of one second and a volume shrinkage after 100 hours at 24O ⁰ C of 5.1 · #

Example 3

To a suspension out

30.0 parts of a mixture of Diisocyaxiatu-dlphenylnethan and Polyphenyl-Polyiethylen-PolylaoGyanat «with an NCO content from 30 to 32 0ew «£,

56.1 Sharing an adipic acid-diethylenglycol-traethylolpropane polyesters with a molecular weight of approximately 2000 and a hydroxyl number of 60-3 and

35 "0 parts melamine adds" to tinter stirring at room temperature

a solution

3.0 parts of tris (dimethyla «inomethyl) phenol, 15 # 0 parts of monofluorotrichlor» etlmn _# 15 * 0 parts of melamine, 10.0 parts of TrlB (chlerlt ^ 7l) pheaphate,

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1.0 part of a silicone-based foam stabilizer (DC 193

from Dow Corning Corp., Midland, Michigan) and 0.5 part of Antifoam A (from Dow Coming Corp. * Midland). After a dwell time of 14 seconds and a rise time of A rigid foam with a density of 211 g / dnr and an extinguishing time of 0 to 1 seconds is obtained for 2.5 minutes.

Example 4

To a suspension out 15.0 parts of a branched polyalkylene ether polyol

Based on methylolpropane propylene oxide with a hydroxyl number of 350 to 400, 3.5 parts of red phosphorus, 5.0 parts of a 50 mol- # lgen solution of tetrakis- (hydroxy-

ethyl) natriua-borate in ethylene glycol, 40.0 parts of melamine, 20.0 parts of tris-chloroethyl phosphate, 15.0 parts of monofluorotrichloromethane,

1.0 part of a silicone-based foam stabilizer and 0.5 part of turkish red oil are stirred at room temperature 100.0 parts of a polyphenyl-polymethylene-polyisooyanate with an NCO content of 30 added.

After a Verweilzelt of 20 seconds and a rise time of 100 seconds obtained nan a fine-celled rigid foam which was dimensionally stable after heat treatment of 100 hours at 200 ⁰ C, with a volume weight of 45 g / d "r and a Verlöschzeit of 0 seconds.

Examples 5 to 8

The rigid foams were produced analogously to the information in Example 2. The product composition and the physical Properties are summarized in Table I.

The examples show that rigid foams that instead of

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Contains tris (chloroethyl) phosphate melamine incorporated, with the same extinction times have significantly lower volume losses.

Examples 9 to 22

To a suspension of a glycerol-propylene-glycol polyetherol with a molecular weight of 450 and an OH number von 400, a foam stabilizer based on silicone (DC 190 from Dow Corning Corp., Midland, Michigan), tetrakis (hydroxyethyl) sodium borate, monofluorotrichloromethane and the Flame retardants are added to a mixture of diisocyanato-diphenylmethane and polyphenylpolymethylene-polyisooyanate with an NCO content of 30 ° with stirring at room temperature.

The product compositions and physical properties are summarized in Table II.

The examples show that the rigid foams, which instead of tris (chloroethyl) phosphate contain melamine inoorporlert, have shorter extinguishing times and lower weight loss

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Table I. Examples

Comparative examples

5a

6a

7a

O CD CO »

Mixture of diisocyanato-diphenylmethane and polyphenyl-polymethylene-polyisocyanate NCO content 30 to 32 % (parts)

Adipic acid diethylene glycol trimethylolpropane polyester, MW 2000, OH number 60 ± 3

Parts

Diamino diphenyl sulfone parts Melamine parts

Tris (chloroethyl) phosphate parts of 2,4,6-tris-dimethylamino-methylphenol (Parts)

Foam stabilizer DC I90 from Dow Corning Corp., Midland (parts of hemostabilizer DC 193 (Dow) (parts Monofluorotrichloromethane

Dwell time

Rise time

Hardening time

Hand weight

Yolumensohwund near each

at 150, 200 and 250 ^° C

The extinction time

Habitus

Divide seconds seconds seconds

(g / dar 12 hours

(Seconds)

58.93

10.02 3.89

14.74 4.72

0.59

7.07 4,240 36O

17.4 0

56.47

14.12

0.62

16.94

4.52

0.56! 6.78

240 360

69

3.4 0

56.47

14.12 0.62

4.52

0.565 6.78

12th

200

36O

75

13.7, 0

62.17

5.31, 18.65

4.97

0.93

7.46

300

• · e 54

9.8 1.5

fine to medium cell

62.17

5.31

18.65 4.97

0.93

7.46

900 β x 66.3

21.4 1.5

49.71

8.77 29.24

2.92

Ο, 58ί

8.77 5

200

400

74

49.71

8.77

29.2 2.92

8.77

18o

400

85

10

0 0.5 medium-cell

K) LO 4> GO OO CO OO

Table II

Examples 9 10 11 flaky cells I. 12th 13th 14th I. 100 [rlaalg 15th 16 17th 18th 19th bar 20th 21 Very cool- 22nd Comparison examples hard I. 68 rings Mixture of diisocyanato ge diphenylmethane and poly 50 phenyl-polymethylene-poly- not brittle: strength isocyanates / NCO content $ 30 100 25th 100 100 100 100 (Parts) 100 100 100 100 100 100 100 100 Glycerine propylene glycol 1 polyetherol j & MG 450 50 20th 20th 20th 20th OH number 400 (parts) 50 50 50 50 15th 20th 20th 20th 20th Tetrakis (hydroxyethyl) 25th 10 10 10 10 sodium borate (parts) 2.5 2.5 25th 25th 30th 10 10 10 10 Foam stabilizer DC 190 1 1 1 1 1 (Dow Corning Corp.) (parts) 1 1 1 1 30th 1 1 1 1 Bfonofluorotriohlomethane 15th 85 15th 15th 15th 15th (Parts) 15th 15th 15th 15th 200 15th 15th 15th 15th Tri $ - (chloroethyl) phosphate Wed 60 - 20th 30th 40 (Parts) - - - m> - 6 - - - - • - Wed Melamine (parts) 10 20th 30th 40 20th 10 20th 30th 40 30th 2 ° 30th 30th Dwell time (seconds, 25th 30th 35 40 60 29.3 30th 30th 25th 20th 70 80 80 100 Rise time (seconds, 65 80 QO 110 120 coarse-celled P.
80 70 65 «5 80 90 90 150 HXrt tent (seconds) 130 160 180 200 40.5 hard 28 80 70 50 : 21 26th 26th 39.5 Space weight (g / dm?) 43 51 65 57 brenr 2 35 39 46 0 burn 3 1 1.5 Release time (seconds) 8th 6th 2.5 4th bar not: 2 1 65.5 brittle 18.6 1.4 36.6 21.7 28.4 Weight loss (#) 20.2 13.4 7th 14.1 de 21 15.7 coarse-celled rough Habitus fine cell strength ge cellular low fTJI ge
schru ■ i · · A fumes

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Examples 23 to 26

To a suspension of a mixture of diisocyanatodiphenylmethane and polyphenyl polymethylene polyisocyanate with an NCO content from 30 to 32 wt. # and melamine is added with stirring at room temperature. Mixture of a branched polyether polyol based on trimethylolpropane propylene oxide with an OH number of 35 * water and an 80% strength by weight solution of tetrakis (hydroxyethyl) sodium borate in ethylene glycol as a catalyst. The reaction mixture is then allowed to foam.

The product compositions and physical properties of the resulting semi-rigid polyurethane foams are summarized in Table III.

The examples show that the polyurethane foams with increasing Melamine content have a higher density and shorter extinguishing time.

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Table III

Examples 25th 24 25th 26th Comparison
example Mixture of diisocyanato-diphenylmethane
and polyphenyl polymethylene polyisocyanate
NCO content 50 to 52 % (parts)
Melamine (parts)
Polyether polyol based on trimethylol
propane-propylene oxide, OH number 55 (parts)
Water (parts)
Tetrakis (hydroxy * thyl) sodium borate
80 percent by weight in ethylene glycol (parts) 100
10
100
2.8
5 ipo
20th
100
2.8
5 100
50
100
2.8
5 100
40
100
2.8
'5 100
100
2.8
5 ^T ° P ^ftime (seconds)
Rise time (seconds)
Hardening time (seconds)
Rough weight (g / dnr)
Time to expire (seconds) 22nd
70
140
. 55
15-20 26th
80
160
65
5-8 50
150
240
75
1-2 55
150
270
85
0 20th
65
155
45
> 25 Habitus elastic, open-cell, good damping properties

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If

Example 27 to 30

The production of isocyanurate-containing coating agents took place by mixing the starting components at room temperature.

The product compositions and the physical properties of the polyurethane coating compositions obtained are shown in Table IV summarized.

The examples show that the pot life of the coating agent with increasing melamine content and the extinguishing time decreases.

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Table IV

Examples 27 28 29 30th Comparison
example hard, elastic, good adhesive force Polyester polyol based on adipinstituent-
Glycerine diethylene glycol, OH number 155
(Parts) 100 100 100 100 100 Filler (Zeolite T from BAYEH AG,
Leverkusen) (parts) 3 3 3 3 3 Tetrakis (hydroxy & thyl) sodium borate
(Parts) 2.5 2.5 2.5 2.5 2.5 Mixture of diisocyanato-diphenylmethane
and polyphenyl polymethylene polyisocyanate
NCO content 30 to 32 % (parts) 100 100 100 100 100 Melamine (parts) 10 20th 30th 40 - Pot life (seconds) 33 36 40 45 30th Curing time (minutes) approx. 15 approx. 15 approx. 15 3a. 15th approx. 15 * Loosening time (seconds) 10-12 4-5 0-2 0 > 15 Habitus

O OJ

ro ο ο

Claims (1)

Claim A process for producing flame-retardant, isocyanurate Polyurethaiücunststoffen of polyisocyanates, catalysts and optionally polyols, blowing agents and auxiliaries, characterized in that the polyurethane plastics from 2.5 to 50 wt.% Melamine, based on the total weight of the reaction mixture, as a flame retardant incorporated therein. Elastogran GmbH p. 50981 5/1067