JPS6318607B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyurethane composition for obtaining a cured product that uses a liquid diene polymer and has excellent elasticity and low-temperature properties, as well as excellent low heat generation properties. BACKGROUND ART Recently, there has been a strong demand for simplifying manufacturing processes and improving productivity in tires for vehicles such as automobiles, anti-vibration rubber, etc., and it has been proposed to use liquid rubber instead of solid rubber. Furthermore, there is a strong demand for safety in automobile tires, and non-puncture tires have been proposed to prevent tire blowouts that directly lead to car accidents. This non-puncture tire is a pneumatic tire filled with an elastomer, and filling it with a polyurethane elastomer is being considered. However, all of these uses require excellent physical properties, and in addition to the elastic properties of rubber, low-temperature properties, especially excellent low heat generation properties, are required. A liquid composition for obtaining the body has not been obtained. The present inventors have conducted extensive research to obtain a cured product that has low heat generation properties without impairing the excellent properties originally possessed by liquid diene polymers, and as a result, the terminal isocyanate precipitates identified The present invention was completed based on the discovery that a polyurethane composition in which a polymer is prepared in advance by reaction and a polyether polyol with a certain molecular weight range or a plasticizer is added to the prepolymer becomes a cured product with excellent low heat generation properties. I came to the conclusion. That is, the present invention comprises (A) two or more compounds containing a liquid polybutadiene obtained by adding polyoxypropylene glycol (including an ethylene oxide adduct) and/or a castor oil-based polyol to a liquid polybutadiene containing terminal hydroxyl groups, and (B) an organic diisocyanate. A polyurethane composition obtained by blending a terminal isocyanate prepolymer obtained by the reaction with a polyoxypropylene triol (including an ethylene oxide adduct) having a molecular weight of 700 to 5000, or a polyurethane composition obtained by further blending a plasticizer with this composition. It is about things. The polyurethane composition according to the present invention is a basic composition consisting of a terminal isocyanate prepolymer containing at least liquid polybutadiene and a polyoxypropylene triol having a molecular weight of 700 to 5000, and provides an elastic cured body through a urethane reaction. . The present invention will be specifically explained below. The terminal isocyanate prepolymer in the present invention is essentially a liquid polybutadiene containing a terminal hydroxyl group, and optionally a liquid polybutadiene containing a terminal hydroxyl group containing polyoxypropylene glycol (including an ethylene oxide adduct) or castor oil-based polyol alone or in combination. It can be obtained by reacting the containing compound with a diisocyanate compound. The liquid diene polymer in the present invention is a liquid polybutadiene containing terminal hydroxyl groups, and has a number average molecular weight of 500 to 25,000. In the present invention, a prepolymer is basically obtained by reacting this liquid polybutadiene with an organic diisocyanate compound, but it also includes the combined use of a polyether polyol and a castor oil polyol as the polyhydroxy compound. be. Examples of the polyether polyol include polyoxypropylene glycol and its ethylene oxide adduct. The amount of ethylene oxide added is usually 30% by weight or less. Castor oil polyol is known as an esterified product of ricinoleic acid and polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol, etc.). Specifically, ethylene oxide is added to an esterified product obtained by adding propylene oxide and/or ethylene oxide to a polyhydric alcohol and then reacting it with ricinoleic acid, or an esterified product obtained by reacting ricinoleic acid and a polyhydric alcohol. and/or products obtained by adding propylene oxide. In any case, in the present invention, the polyhydroxy compound used in the prepolymer has two to three functional groups. Next, examples of organic diisocyanate compounds include conventional aromatic, aliphatic and alicyclic compounds, such as tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, liquid modified diphenylmethane diisocyanate, and polymethylene diisocyanate. Examples include polyphenyl isocyanate, xylylene diisocyanate, cyclohexyl diisocyanate, cyclohexanephenylene diisocyanate, naphthalene-1,5-diisocyanate, isopropylbenzene-2,4-diisocyanate, and addition reaction products of polypropylene glycol and tolylene diisocyanate. The reaction for obtaining the terminal isocyanate prepolymer is usually carried out under conditions of an inert gas flow such as dry nitrogen, a reaction temperature of 30 to 100°C, and a reaction time of 10 minutes to 10 hours. The isocyanate group content of this prepolymer is preferably in the range of 5 to 15% by weight. The polyurethane composition of the present invention has a molecular weight of 700 to 5000 with respect to the terminal isocyanate prepolymer.
polyoxypropylene triol (including ethylene oxide adduct), preferably with a molecular weight of 1000~
4500 polyoxypropylene triol (including ethylene oxide adduct) with an NCO/OH ratio of 0.8
-1.5, preferably 0.9-1.1. In the present invention, a substance with a molecular weight within this range must be used; outside this range, even if the molecular weight is large or small, it is not possible to obtain an elastic cured product that has the low heat generation properties that are the object of the present invention. . As the ethylene oxide adduct of polyoxypropylene triol, one in which the amount of ethylene oxide added is 30% by weight or less is used. In the composition of the present invention, it is essential that the terminal isocyanate prepolymer contain a liquid diene polymer chain. Therefore, for example, if a hydroxyl group-containing liquid diene polymer is used as a raw material for a polyhydroxy compound, it is not possible to obtain the desired elastic cured product of the present invention. However, using liquid polybutadiene in an amount of 40% by weight or less with respect to polyoxypropylene triol with a molecular weight of 700 to 5000 or its ethylene oxide adduct as a raw material for a polyhydroxy compound does not allow the liquid diene polymer in the composition to Even though the content is increased, it is possible to obtain an elastic cured body with low heat build-up. The polyurethane composition of the present invention has excellent low heat generation properties as detailed above, but according to research by the present inventors, it is possible to reduce heat generation by adding a plasticizer to the composition. It became clear that the characteristics were further improved. Therefore, the present invention includes the invention of a polyurethane composition containing a plasticizer. Plasticizers used here include phthalates such as dioctyl phthalate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, butylbenzyl phthalate, adipates such as dioctyl adipate, sebacates such as dioctyl sebacate,
These include phosphates such as tris dichloropropyl phosphate and cresyl phenyl phosphate, naphthenic oils, aroma oils, and alkyl aroma oils. The amount of these plasticizers added is preferably 30% by weight or less in the composition, especially
10 to 20% by weight is preferred. The method of adding these plasticizers is not particularly limited, and they can be added, for example, during the production of the prepolymer. An elastomer product can be obtained from the polyurethane composition of the present invention by adding a catalyst as necessary and causing a curing reaction, usually under heating.
Examples of the catalyst used here include urethane catalysts such as di-n-butyltin dilaurate, stannath octoate, triethylenediamine, diethylenediamine, triethylamine, naphthenic acid metal salts, and octylic acid metal salts. Furthermore, pigments, stabilizers, fillers, etc. can be added if necessary. As detailed above, the polyurethane composition of the present invention has the elasticity and low-temperature properties of liquid polybutadiene, and can provide an elastic cured body having excellent dynamic low heat generation properties and appropriate hardness.
This makes it possible to develop new uses for liquid polybutadiene. It is particularly useful as a composition for filling pneumatic tires instead of air, making it possible to provide safe tires. Furthermore, it makes it possible to easily and efficiently produce a wide range of products such as vibration-proof materials where dynamic heat generation is a problem. The present invention will be explained in more detail with reference to Examples below. Example 1 Liquid polybutadiene containing terminal hydroxyl groups (number average molecular weight 2800, viscosity 50 poise (30°C), hydroxyl group content
Dry 100 parts by weight of a 60:40 mixture of 0.83meq/g) and polyoxypropylene glycol (number average molecular weight 3000) and 60.4 parts by weight of a liquid modified product of 4,4-diphenylmethane diisocyanate (NCO content 28.75% by weight). The reaction was carried out at 40° C. for 3 hours under a nitrogen atmosphere to obtain a terminal isocyanate prepolymer. The NCO content of this prepolymer was 9.0% by weight. Polyoxypropylene triols or ethylene oxide adducts of polyoxypropylene triols with various molecular weights are added to this prepolymer.
The NCO/OH ratio was 1.05, and 0.14% by weight of di-n-butyltin dilaurate was added to the prepolymer as a catalyst. After stirring and defoaming, it was poured into a mold and heated at 120°C for 1 hour. I pressed. Then, post-curing was performed at 70°C for 12 hours to create a cured product. Table 1 shows the measurement results of various tests conducted using this cured product. As is clear from Table 1,
When the molecular weight of polypropylene triol (including ethylene oxide adducts) is in the range of 700 to 4,400, it has extremely low heat build-up and is excellent. In addition, various test methods were performed according to the following methods. a Dynamic heat build-up Gutsuduritsu flexometer (ASTM D
-623) Temperature: 100°C, Stroke: 0.175 inches, Load: 22 pounds, Frequency: 1800 rpm Test time: 25 minutesb Permanent strain Calculated from the following formula using samples before and after measurement with a flexometer. The height after the test was measured after the test was left at room temperature for 24 hours. Permanent strain [%] = (Height of the sample before the test) - (Height of the sample after the test) / Height of the sample before the test x 100 c Tensile strength, elongation, 50% modulus: JISK -
6301 d Tear strength: JIS K-6301 e Hardness: JIS K-6301 f Impact modulus: JIS K-6301

[Table] Example 2 Polyol having the composition shown in Table 2 and liquid modified MDI (liquid modified product of 4,4-diphenylmethane diisocyanate (NCO content 28.75% by weight)) were mixed at 40°C under a dry nitrogen atmosphere for 30 minutes. A terminal isocyanate prepolymer was obtained by reacting for a time. The NCO content of this prepolymer was 9.0% by weight. Polyoxypropylene triol with a molecular weight of 1500 was added to this prepolymer so that the NCO/OH ratio was 1.05. , furthermore, 0.10% by weight of di-n-butyltin laurate based on the prepolymer as a catalyst.
After adding, stirring and mixing, and defoaming, pour into a mold and heat at 120°C.
Heat and pressure was applied for an hour. Then, post-curing was performed at 70°C for 12 hours to create a cured product. Table 2 shows the results of measurements carried out in accordance with Example 1 using this cured product.

[Table] Example 3 A mixture of polyoxypropylene triol with a molecular weight of 3000 and liquid polybutadiene containing terminal hydroxyl groups was added to the terminal isocyanate prepolymer used in Example 1 so that the NCO/OH ratio was 1.05, and di- Example 1: 0.14% by weight of n-butyltin dilaurate was added to the prepolymer.
A cured product was prepared according to the method and the measurement results are shown in Table 3.

[Table] Example 4 Polyoxypropylene triol with a molecular weight of 3000 was added to the terminal isocyanate prepolymer used in Example 1 so that the NCO/OH ratio was 1.05, and di-n-butyltin dilaurate was added to the prepolymer as a catalyst. 0.1% by weight of the plasticizer shown in Table 4 was blended, a cured product was prepared according to Example 1, and the measurement results are shown in Table 4.

【table】

Claims (1)

[Scope of Claims] 1 (A) two or more compounds containing a liquid polybutadiene obtained by adding polyoxypropylene glycol (including an ethylene oxide adduct) and/or a castor oil-based polyol to a liquid polybutadiene containing a terminal hydroxyl group; and (B) A polyurethane composition comprising a terminal isocyanate prepolymer obtained by reacting an organic diisocyanate with a polyoxypropylene triol (including an ethylene oxide adduct) having a molecular weight of 700 to 5000. 2 (A) Two or more compounds containing a liquid polybutadiene prepared by adding polyoxypropylene glycol (including an ethylene oxide adduct) and/or a castor oil polyol to a liquid polybutadiene containing terminal hydroxyl groups and (B) an organic diisocyanate. A polyurethane composition obtained by blending the obtained terminal isocyanate prepolymer with a polyoxypropylene triol (including an ethylene oxide adduct) having a molecular weight of 700 to 5000 and a plasticizer. 3. The polyurethane composition according to claim 2, wherein the amount of plasticizer blended in the composition is 30% by weight or less.