JPH058728B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyurethane having excellent hydrolysis resistance, mold resistance, oil resistance, adhesiveness, abrasion resistance, etc. Furthermore, the polyol used in the present invention is a liquid with extremely low viscosity and has excellent processability and workability.
The present invention relates to a method for producing polyurethane that can be applied to foams, microcellular, cast elastomers, paints, adhesives, waterproofing agents, flooring materials, sealing materials, caulking materials, and thermoplastic polyurethane elastomers. Polyether polyols and polyester polyols are generally used in the production of polyurethane, but polyester polyols are superior in terms of abrasion resistance, strength and elongation, oil resistance, solvent resistance, adhesive performance, etc. However, when comparing polyester polyols and polyether polyols of the same molecular weight, the polyester polyols with greater intermolecular cohesive force become liquids or solids with higher viscosity.
When used as a solvent-free type or high solids for the above applications, polyether polyols, especially polypropylene polyols, are better in workability when they are liquid and have a lower viscosity, and are also convenient when adding fillers, pigments, etc. is preferred and used. However, as mentioned above, polyurethane based on polypropylene polyol has problems in mechanical strength, abrasion resistance, and adhesiveness. Furthermore, polyester polyol is indispensable for forms that require frame lamination (bonding with cloth etc. by heat fusion) and for adhesives from the viewpoint of adhesive properties. For this reason, copolymerization of polyester polyols or the use of polyester-modified polyether polyols are known, but they do not fully satisfy the required performance as described above, and the introduction of ester groups results in unnecessary hydration resistance. The reality is that this causes deterioration in degradability, mold resistance, etc. As a result of various studies on the production method of polyurethane suitable for the above-mentioned uses, the present inventors found that when producing polyurethane by reacting a polyol with a polyisocyanate and, if necessary, a chain extender, the polyurethane is It has been found that the above problems can be solved by using a polyester polyether polyol having an average molecular weight of 600 to 7000 and having a polypropylene oxide group and a polypropylene oxide group having a molecular weight of 400 or more. The polyol used in the present invention is a liquid with an extremely low viscosity, so it has excellent workability and high reactivity with isocyanates.Moreover, the polyurethane obtained by the method of the present invention has almost the same durability as polyether polyurethane. It is hydrolyzable and has the characteristics of polyester polyurethane. within the molecule Specifically, a polyester polyether polyol having an average molecular weight of 600 to 7000 having a polypropylene oxide group and a polypropylene oxide group having a molecular weight of 400 or more is a 3-
It is obtained by polycondensing a mixed polyol of methyl-1,5-bentaldiol and polypropylene polyol with a dicarboxylic acid such as adipic acid. Polypropylene polyol specifically refers to polypropylene glycol or a polyol obtained by adding polypropylene oxide to a trifunctional or higher functional alcohol such as trimethylolpropane or glycerin. The above-mentioned polyester polyether polyol in which polypropylene oxide groups are modified in the same molecule in the form of blocks is 3-methyl-
Compared to the case where a polyester polyol made from 1,5-pentanediol and adipic acid and a polypropylene polyol are used together by blending,
This gives favorable results in terms of overall physical properties of the resulting polyurethane. Even when used as a two-component curing type, polyester polyether polyol in which the polypropylene oxide group is modified into a block shape naturally provides more preferable performance in terms of the compatibility of the two types of polyols mentioned above. becomes. In the present invention, 3-methyl-1,
The weight ratio of 5-pentadiol to polypropylene oxide groups is preferably 1:0.5 to 4. Note that the polyester polyol made from 3-methyl-1,5-bentanediol and adivic acid is an amorphous polymer and is a liquid with low viscosity at room temperature.
Therefore, the polyurethane obtained from the polyurethane is excellent in workability and has the feature that crystal hardening of the soft segment is not observed. On the other hand, since polypropylene polyol is also a liquid with an extremely low viscosity, the polyol of the present invention has an extremely low viscosity, and is lower in viscosity than a polyester polyol made from 3-methyl-1,5-pentanediol alone or adipic acid. Therefore, when used for foam, microcellular, adhesives, cast elastomers, waterproof materials, flooring materials, etc., it not only has excellent workability but also has excellent hydrolysis resistance and adhesive properties. It has both the advantages of ether type and polyester type. The molecular weight of the polyol used in the present invention is in the range of 600 to 7,000; if it is less than 600, the low temperature properties and flexibility will be poor, and if it is more than 7,000, it will be unfavorable in terms of strength and physical properties. Note that 3-methyl-1,5- used in the present invention
Polyesters from pentadiol have very good hydrolysis resistance and are therefore compatible with other glycols such as ethylene glycol, butanediol,
From the viewpoint of hydrolysis resistance, it is preferable not to use too large amounts of 1,6-hexanediol, diethylene glycol, propylene glycol, etc. By using polypropylene polyol, 3-methyl-1,5-pentanediol, and polyester polyether polyol made from a dicarboxylic acid such as adipic acid, the effects of the present invention in terms of hydrolysis resistance and the like are significantly exhibited. Furthermore, dicarboxylic acids used in the present invention include succinic acid, glutaric acid, adipic acid, azelaic acid, etc., and adipic acid and azelaic acid are most preferred. Further, in producing the polyol of the present invention, it is also permissible to use a small amount of polyhydric alcohol such as trimethylolpropane, glycerin, and pentaerythritol. Examples of the organic polyisocyanate used in the present invention include diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6
- Aromatic diisocyanates such as tolylene diisocyanate, phenylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3'-dichloro-4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, tolylene diisocyanate, and hexamethylene Examples include aliphatic or aliphatic diisocyanates such as diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate. Polyisocyanates may be used alone or in combination. Furthermore, in the synthesis of polyurethane, low molecular weight compounds having two or more active hydrogen atoms are usually used as chain extenders, and these active hydrogen atom-containing compounds can also be used in the method of the present invention. Representative examples of these active hydrogen atom-containing compounds include ethylene glycol, butanediol, propylene glycol, 1,6-
Diols such as hexanediol, 1,4-bis(β-hydroxyethoxy)benzene, 1,4-cyclohexanediol, bis(β-hydroxyethyl)terephthalate, xylylene glycol, water, hydrazine, ethylenediamine, propylenediamine, Examples include xylylene diamine, isophorone diamine, piperazine, phenylene diamine, tolylene diamine, adipic acid dihydrazide, isophthalic acid dihydrazide, and the like, and these compounds may be used alone or in combination. Furthermore, if necessary, a monohydric low-molecular alcohol, a low-molecular amine, or the like may be used as a modifying agent. As for the operation method for obtaining polyurethane, known urethanization reaction techniques are used. For example, by mixing a polyol and a low-molecular compound having active hydrogen, the number of active hydrogen atoms in these compounds and
Add a polyisocyanate compound in an amount such that the ratio of NCO groups is about 1:0.7 to 1:1.3 at 60 to 130℃.
Polyurethane can be obtained by reacting at a temperature of about
The molar ratio of NCO and OH should be as close to 1 as possible.
This reaction can also be carried out in a solvent consisting of one or more of ethyl acetate, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, isopropanol, methyl ethyl ketone, toluene, ethyl cellosolve, and the like. The concentration at this time is preferably within the range of 10 to 70% by weight. The present invention will be specifically explained below using Examples.
In addition, in the examples, hydrolysis resistance refers to the obtained thickness.
The tensile strength retention rate of a 200μ film after being left for 6 weeks in an atmosphere with a relative humidity of 95% and a temperature of 70°C (jungle test conditions) was also expressed. Solvent resistance was measured by making a polyurethane film into a 200 μm thick film and measuring the degree of weight swelling after immersing the film in toluene for 24 hours. Abrasion resistance was measured by using a Gakushin type abrasion tester and measuring the weight loss (mg) after 200 abrasions at a load of 500g with a sheet of polyurethane CC600 and emery paper. Furthermore, the polyols, polyisocyanates, and chain extenders used as raw materials for polyurethane used in the Examples are shown using abbreviations, and the relationship between the abbreviations and compounds is as shown in Table 1. Examples 1 to 3, Comparative Examples 1 and 2, Reference Example 1 Polyurethane was manufactured using the raw materials shown in Table 2. That is, predetermined amounts of polyol, polyisocyanate, and chain extender were reacted in dimethylformamide at 75° C. under nitrogen to give a solid content of 30% by weight to obtain polyurethane. After adjusting the polyurethane concentration of this solution to 10%, this solution was cast onto a glass plate and dried to obtain a film with a thickness of 200 μm. Hydrolysis resistance and solvent resistance were measured using this film.

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Claims (1)

[Claims] 1. When polyurethane is produced by reacting a polyol with a polyisocyanate and, if necessary, a chain extender, the polyurethane is added as a polyol component to the molecule. 1. A method for producing polyurethane, comprising using a polyester polyether polyol having an average molecular weight of 600 to 7,000 and having a polypropylene oxide group and a polypropylene oxide group having a molecular weight of 400 or more.