JPS6315934B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses a specific liquid chloroprene-based polymer having at least two hydroxyl groups in the molecule as a part of the polyol, and has improved heat resistance and hydrolysis resistance by including polychloroprene units in its structure. The present invention relates to a new polyurethane composition. Conventional polyurethane is polyether polyol,
Methods of formation by reaction of polyols such as polyester polyols with polyisocyanates such as tolylene diisocyanate and diphenylmethane diisocyanate are known. However, polyurethane formed by such known methods has excellent mechanical strength and abrasion resistance due to urethane bonding, but due to its polymer structure, it has poor heat resistance (easily softened by heat at temperatures between 80°C and 100°C or higher). There were problems with hydrolysis resistance due to hot water of 50℃ or higher. The present inventor conducted various studies in order to improve the disadvantages of polyurethane, and found that the conventional problems could be significantly improved by using a specific liquid chloroprene polymer described below as a part of the polyol. This is what led to this. That is, the present invention has at least two hydroxyl groups in the molecule, and at least one of them is based on 100 parts by weight of a polyol having at least two terminal hydroxyl groups and having a molecular weight of 6,000 or less and having no polychloroprene units. Liquid chloroprene polymer with a number average molecular weight of 500 to 6000 bonded to the end of the molecule15
~300 parts by weight and 100 parts by weight of the liquid chloroprene polymer
The vulcanization accelerator for liquid chloroprene polymers that does not substantially react with isocyanate groups based on parts by weight
The present invention provides a composition capable of forming a polyurethane containing 0.3 to 30 parts by weight and an isocyanate as a curing agent for the polyol and the liquid chloroprene polymer within a range that satisfies the following formula. Formula 0.9≦I/H≦1.2 (where H is the hydroxyl group equivalent in the polyol having no polychloroprene unit and the liquid chloroprene polymer, and I is the isocyanate group equivalent in the polyisocyanate compound or the regenerated polyisocyanate compound. (respectively) A molecular weight that does not contain polychloroprene units having at least two terminal hydroxyl groups in the molecule used to form the composition of the present invention.
Examples of polyols having a molecular weight of 6000 or less include polyether polyols such as polyethylene glycol, polypropylene glycol, and polyoxytetramethylene ether glycol, polyethylene adipate, polypropylene adipate, polybutylene adipate, polyhexamethylene adipate,
Polyester polyols such as polyhexamethylene phthalate, polyester amide polyols, epoxy-modified polyester polyols, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol , neopentyl glycol, 1,4-butenediol, 1,5
-pentanediol, 1,6-hexanediol, 2-ethylhexane-1,3-diol, trimethylolpropane, pentaerythritol,
Examples include polyols such as castor oil, and among these, polypropylene glycol and polyoxytetramethylene ether glycol are particularly preferably used from the viewpoint of compatibility with other polyols and ease of acquisition. It is not limited to. The liquid chloroprene-based polymer used in the present invention is a type of thermosetting polymer similar to ordinary chloroprene-based polymers, and its crosslinking reaction tends to be accelerated in a heated atmosphere, and its isocyanate-cured products harden even at high temperatures. Not only does it not cause any deterioration, but it also shows extremely excellent hydrolysis resistance. Therefore, it is presumed that by cross-linking such liquid chloroprene polymer chains into conventional polyurethane compositions, the heat resistance and hydrolysis resistance of the resulting polyurethane can be improved. The liquid chloroprene polymer used in the present invention has at least two hydroxyl groups in the molecule, and at least one of the hydroxyl groups is bonded to the end of the molecule, and has a number average molecular weight of 500 to 6000. limited to things. When the number average molecular weight of the liquid chloroprene polymer is less than the above range, the number of crosslinkable points of the polychloroprene present in the resulting composition is extremely small, and the number of crosslinkable points of the polychloroprene in the presence of the vulcanization accelerator for the liquid chloroprene polymer is extremely small. Even in this case, crosslinking hardly progresses, and the heat resistance of the resulting polyurethane
Hydrolysis resistance cannot be improved, and if the above range is exceeded, the viscosity of the resulting composition becomes extremely high, and workability is significantly impaired. The bonding position of the hydroxyl group introduced into the liquid chloroprene polymer molecule may be either at the end of the molecule or randomly located within the molecule, but at least one is bound to the end of the molecule. In addition, the optimum number of hydroxyl groups to be introduced into the liquid chloroprene polymer chain is 2 to 4; if it is less than 2, a sufficient cured product cannot be obtained, and if it is more than 4, the liquid chloroprene polymer Combining is very expensive and economically disadvantageous. The liquid chloroprene polymer used in the present invention is limited to 15 to 300 parts by weight per 100 parts by weight of the polyol without polychloroprene units. If it is less than the above range, the heat resistance, hydrolysis resistance, etc. of the resulting polyurethane will not be sufficiently improved, and if it exceeds the above range, the viscosity of the resulting composition will become extremely high, impairing workability. However, it has some drawbacks, so a range of about 20 to 200 parts by weight is particularly preferred in practice. As a method for producing a liquid chloroprene-based polymer having a hydroxyl group in the molecule, (1) a monomer containing chloroprene as the main component and the formula

[Formula] (wherein n is 1 or 2 and R is a hydrocarbon group having 1 to 3 carbon atoms.) Method by solution copolymerization with a hydroxyl group-containing monomer, (2) chloroprene and A method in which a radical telomerization copolymer with 1-chlorobutadiene-1,3 is reacted with a tertiary amine having a hydroxylalkyl group to introduce a hydroxyl group into the polymer; (3) radical telomerization of chloroprene with hydrogen peroxide; Examples include a method of melization polymerization, and (4) a method of polymerizing chloroprene using a chain transfer agent having a hydroxyl group such as 2-mercaptoethanol. Among these methods, methods (3) and (4) are used to introduce a hydroxyl group to the terminal end of the polymer. Therefore, (1)
Or, if method (2) is used, it may be used in combination with method (3) or (4). Method (1) is easy to polymerize, and the resulting polymer has good compatibility with polyols that do not have polychloroprene units. Although those produced in combination are particularly preferred, the method for producing the liquid chloroprene polymer is not limited to the above-mentioned methods. In addition, in these production methods, it is of course possible to use a mixture containing 50% by weight or more of chloroprene as a main component and a monomer copolymerizable with it, such as styrene, acrylonitrile, acrylic, etc., instead of chloroprene. Acids, vinyl compounds such as methacrylic acid, acrylic esters, and methacrylic esters, and conjugated diene compounds such as 1,3-butadiene, 2,3-dichlorobutadiene-1,3, and isoprene are used as appropriate. Therefore, the liquid chloroprene polymer used in the present invention includes all polymers that contain a polychloroprene structure as a main component and satisfy the above-mentioned limiting conditions. The vulcanization accelerator for liquid chloroprene polymer used in the present invention is a vulcanization accelerator for polychloroprene that does not substantially react with isocyanate groups, and the amount used is 0.3 parts by weight per 100 parts by weight of the liquid chloroprene polymer. -30 parts by weight. When it is desired to improve the heat resistance and hydrolysis resistance of the composition obtained in the present invention, it is advantageous to accelerate the vulcanization reaction based on the polychloroprene structure during curing, and also to improve the vulcanization reaction that occurs during thermal deterioration of polychloroprene. Since hydrochloric acid significantly reduces heat resistance, it is advantageous to use a vulcanization accelerator for polychloroprene as a hydrochloric acid scavenger. If the amount of the vulcanization accelerator is less than the above-mentioned limited range, little effect can be expected in the vulcanization reaction and as a hydrochloric acid scavenger, and if it exceeds the above-mentioned range, no particular effect of adding a large amount will be observed. It is also economically disadvantageous.
Examples of the vulcanization accelerator for polychloroprene include:
Examples include, but are not limited to, metal oxides such as zinc white, magnesia, litharge, and red lead, and organic compound vulcanization accelerators such as zinc butylxanthate. Practically speaking, per 100 parts by weight of the liquid chloroprene polymer, 3 to 30 parts by weight of metal oxide as a vulcanization accelerator for the polychloroprene,
A range of 0.3 to 5 parts by weight of the organic compound vulcanization accelerator is particularly preferred. Further, in the present invention, the polyisocyanate compound or regenerated polyisocyanate compound used as a curing agent for the polyol having no polychloroprene unit and the liquid chloroprene polymer include hexamethylene diisocyanate, cyclohexane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate,
Dimers and trimers of 2,4-tolylene diisocyanate, xylylene diisocyanate, m-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 3,3'-ditoluene-4,4'-
Common polyesters such as diisocyanate, dianisidine diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, and triphenylmethane triisocyanate. Isocyanate compounds or blocking agents such as phenols, lactams, alcohols, mercaptans, imides,
Examples include, but are not limited to, regenerated polyisocyanate compounds obtained using amine, imidazole, imine, and oxime compounds. Further, in the present invention, the ratio of the isocyanate group equivalent of the polyisocyanate compound or the recycled polyisocyanate compound to the hydroxyl group equivalent of the polyol having no polychloroprene unit and the liquid chloroprene polymer is in the range of 0.9 to 1.2. This is because the reaction between these two proceeds almost quantitatively, so if the curing reaction is outside this range, a sufficient curing reaction will not be achieved and it will be difficult to obtain a polyurethane with improved performance. The curing reaction of the composition of the present invention varies depending on the polyisocyanate compound used or the regenerated polyisocyanate compound and the use of the obtained polyurethane, but the temperature range is wide from low to high temperature, usually in the range of 0°C to 120°C. It will be held in When accelerating the curing speed, organic tin compounds such as dibutyltin dilaurate and tin octylate, tertiary amines such as triethylamine, triethylenediamine, and N-methylmorpholine, 1,8-diazabicyclo-(5,4,0 )-Undecene and cyclic amidine compounds such as its organic acid salts can be used as appropriate. With the composition of the present invention, a polyurethane with improved heat resistance and hydrolysis resistance, which are disadvantages of conventional polyurethanes, can be obtained, and in addition, it has weather resistance, ozone resistance,
It is also possible to obtain a material that has practically sufficient resistance in terms of chemical resistance, adhesiveness, and flame retardancy. Therefore, the composition according to the present invention can be applied to various uses such as room-temperature curable or heat-curable compositions, and typical uses include cast molded products, potting materials, lining materials, paints, sealants, and coatings. Examples include, but are not limited to, membrane waterproofing materials, adhesives, foam products, and heat insulating materials. The composition according to the invention can be used as a watertight filler for cables, and can also be incorporated into solvent-borne adhesives based on thermoplastic polyurethane to improve the low-temperature adhesion that polyurethane has. It is also possible. In carrying out the present invention, common compound components such as titanium dioxide, calcium carbonate, silica, inorganic fillers such as carbon black, petroleum oils, phthalate esters, softening agents such as tar, phenolic resin, coumaron indene, etc. Resins such as resin, straight asphalt,
Bituminous materials such as blown asphalt and solvents as compound viscosity modifiers can be incorporated. Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto. Note that all amounts used in the examples are based on weight. In Examples and Comparative Examples, Polymers A to E shown in Table 1, which were produced according to the following polymerization recipe, were used. In addition, since each of Polymers A to E was polymerized using 2-mercaptoethanol as a chain transfer agent, they all have one hydroxyl group at the end of the molecule. The molecular weights of these polymers were measured using an everiometer, and the hydroxyl group content was determined after treating the polymers with acetyl chloride.
It was determined by neutralization titration using a KOH methanol solution. Polymerization recipe Monomer 100 parts 2-mercaptoethanol 1-7 parts Toluene 25-50 parts α,α'-azobis-2,4-dimethylvaleronitrile 0.25-0.75 parts Polymerization temperature 40-55℃ Polymerization time 10-20Hr. Post-treatment After removing unreacted monomers from the polymerization solution by distillation under reduced pressure, it was washed and purified with a large excess of methanol, and then the polymer toluene solution was treated with a vacuum evaporator to isolate a liquid polymer.

[Table] Example 1 Polypropylene glycol with a molecular weight of 1000 (hereinafter
PPG) and polymers A, B, listed in Table 1.
C, E and diphenylmethane diisocyanate (hereinafter referred to as MDI) as a curing agent are mixed in a paint mill with various compounding agents according to the formulation listed in Table 2. The mixture was poured into a 2 mm mold and press cured at 120°C for 1 hour to obtain a cured sheet. The obtained cured sheet was cured at 20° C. for 7 days, and then its performance was evaluated according to the test method of JIS K6301. The results are summarized in Table 2. Here, Test No. 4 is a comparative example when a liquid chloroprene-based polymer not according to the present invention is used, and Test No. 5 is a comparison example of polyurethane when the liquid chloroprene-based polymer according to the present invention is not used. This is an example. As is clear from these results, the composition obtained according to the present invention has significantly improved heat resistance (no softening during heat aging) and hydrolysis resistance compared to the comparative example.

【table】

[Table] Example 2 PPG with a molecular weight of 1000 and Polymer D listed in Table 1
and two types of diphenylmethane diisocyanate (hereinafter referred to as MDI) as a curing agent in a paint mill according to the formulation shown in Table 2. A cured sheet was prepared in the same manner as in Example 1 from a compound obtained. Created. Table 3 shows the results of evaluating the general physical properties, heat resistance, and hot water resistance of these cured products. Test No. 9 is a comparative example of a cured product in which the liquid chloroprene polymer referred to in the present invention was not used. From these results, it is clear that the composition obtained according to the present invention has significantly improved heat resistance (no softening during heat aging) and hydrolysis resistance compared to the comparative example.

【table】

[Table] *During immersion: Unable to measure as it does not retain its original shape due to depolymerization
Example 3 To 100 parts by weight of polypropylene glycol with a molecular weight of 2000, 100 parts by weight of the polymer D listed in Table 1,
NCO content 29.0% as a hardening agent in 5 parts by weight of zinc white
A uniform mixture of 24.8 parts by weight of diphenylmethane diisocyanate and 0.005 parts by weight of dibutyltin dilaurate (the viscosity of this liquid at 20°C is
It is 4200cps. ) was poured into a mold and left at room temperature for 1 day to obtain a cast product. This cast product was placed in a gear oven at 180°C for one day, but almost no deformation was observed.

Claims (1)

[Scope of Claims] 1. For 100 parts by weight of a polyol having at least two terminal hydroxyl groups in the molecule and having a molecular weight of 6,000 or less and having no polychloroprene units, One is the number average molecular weight attached to the end of the molecule
500 to 6000, and 15 to 300 parts by weight of a liquid chloroprene polymer, and 0.3 to 0.3 to 100 parts by weight of a vulcanization accelerator for the liquid chloroprene polymer that does not substantially react with isocyanate groups.
A composition capable of forming a polyurethane, which contains 30 parts by weight and an amount of a polyisocyanate compound or a regenerated polyisocyanate compound that satisfies the following formula. Formula 0.9≦I/H≦1.2 (However, H is the hydroxyl group equivalent in the polyol having no polychloroprene unit and the liquid chloroprene polymer, and I is the isocyanate group in the polyisocyanate compound or the regenerated polyisocyanate compound. 2. Scope of claims in which the liquid chloroprene-based polymer is produced by solution-based copolymerization of a monomer mainly composed of chloroprene and a hydroxyl group-containing monomer represented by the following formula. A composition capable of forming the polyurethane according to item 1. (However, n is 1 or 2, and R is a hydrocarbon group having 1 to 3 carbon atoms.