JPS6258375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to compositions for producing semi-rigid foams or expanded elastomers having improved weather resistance and mechanical properties.

Various semi-rigid polyurethane foams and foamed elastomers have been known, but they all use aromatic isocyanates as raw material isocyanates, and have the disadvantage of yellowing and deterioration. In order to overcome this drawback, the present inventors attempted to produce a semi-rigid foam or foamed elastomer using an aliphatic isocyanate, but the foam cracked and no product with excellent physical properties could be obtained. . The present inventors have conducted various studies in order to obtain a non-yellowing foam with good physical properties. As a result, we have developed a semi-rigid foam or foamed elastomer composition with improved weather resistance and mechanical properties, which is made of a specific prepolymer and a specific polyol. I found something.

That is, the present invention provides a prepolymer having a free isocyanate group content of 35% or less, which is obtained by reacting an aliphatic or alicyclic polyisocyanate with a polyol having a hydroxyl equivalent of 150 or less and an average number of functional groups of 3 or more, 60% or more, a polyol with an average functional group number of 3 or more and a hydroxyl equivalent of 1000 or more,
This invention relates to a composition for producing a semi-rigid foam or foamed elastomer with improved weather resistance and mechanical properties, which comprises a polyhydroxyl compound having a hydroxyl equivalent of 100 or less, a blowing agent, and a catalyst.

The prepolymer which is the above component is obtained by reacting an aliphatic or alicyclic polyisocyanate with a polyol having a hydroxyl equivalent of 150 or less and an average number of functional groups of 3 or more, and its isocyanate group content is preferably 35% or less. It is 20-30%.
In addition, if the isocyanate group content of the prepolymer is 30
If it is larger than %, the odor is strong and the viscosity is low.
Mixing with the polyol component tends to be incomplete.

Examples of the aliphatic or alicyclic polyisocyanate that is a raw material for one of the components include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HMDI), m- and p-xylylene diisocyanate (XDI), and 3-methyl isocyanate. −
3,5,5-trimethylcyclohexyl isocyanate (IPDI), 4-methyl-1,3-cyclohexylene diisocyanate (H ₆ TDI), 4,4-
Methylenebis(cyclohexyl isocyanate)
(H ₁₂ MDI), 2,4'-methylenebis(cyclohexyl isocyanate), 1,3- and 1,4-
Examples include bis(isocyanatomethyl)cyclohexane. These can be used alone or in combination of two or more.

Examples of polyols having a hydroxyl equivalent of 150 or less and an average number of functional groups of 3 or more, which are the other raw materials for the component, include trimethylolpropane, glycerin, pentaerythritol, diglycerin, sorbitol, sucrose, and polyols obtained by adding alkylene oxide to these polyols. Examples include polyether polyols obtained by Furthermore, even difunctional substances such as ethylene glycol can be mixed with polyols having 4 or more functional groups to reduce the average number of functional groups to 3.
The above may be used. When the average number of functional groups is less than 3, deterioration due to light is likely to occur. Furthermore, if the hydroxyl equivalent is greater than 150, curing will be poor and it cannot be used.

The component polyol has a primary terminal content of 60% or more, an average number of functional groups of 3 or more, and a hydroxyl equivalent of 1000 or more. When the hydroxyl group equivalent is less than 1000, rebound and elongation are poor, and when the terminal primary hydroxyl group is less than 60%, the curing reaction is slow and sometimes the form collapses. Specific examples of such polyols include glycerin, trimethylolpropane, pentaerythritol, diglycerin,
Polyethers obtained by adding one or more alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide to polyhydric alcohols such as sorbitol, and also such as succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and phthalic acid. acid, isophthalic acid,
Polycarboxylic acids such as terephthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, maleic anhydride and e.g. ethylene glycol, 1,2- and 1,3-propylene glycol. , 1.4-, 1.3- and 2.3-
Polyester obtained by reacting butylene glycol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol, glycerin, trimethylolpropane, trimethylolethane, diethylene glycol, triethylene glycol, dipropylene glycol, ε-
Examples include polyesters obtained by ring-opening polymerization of caprolactone. These polyethers and polyesters may be used alone or as a mixture of two or more types, as long as the primary hydroxyl group content is within the specified ranges for the average number of functional groups and the hydroxyl equivalent.

The polyhydroxyl compound has a hydroxyl equivalent of 100 or less, and specific examples include ethylene glycol, propylene glycol,
Examples thereof include polyhydroxyl compounds such as 1,4-butylene glycol, glycerin, trimethylolpropane, pentaerythritol, and diglycerin, as well as compounds obtained by adding alkylene oxide to these polyhydroxyl compounds. If the hydroxyl equivalent is greater than 100, the physical properties at high temperatures will deteriorate.

The components in the compositions of the invention are used in amounts of 5 to 30% by weight relative to the components. Also,
and the components are blended so that the NCO/OH equivalent ratio is 1.1.10, preferably 1 to 1.05.

The component blowing agent can be any blowing agent used as a blowing agent in the production of conventional semi-rigid foams and expanded elastomers, typical examples being water, methylene chloride, ethylidene chloride, chloride, etc. Examples include easily volatile organic substances such as vinylidene, monofluorotrichloromethane, difluorochloromethane, difluorodichloromethane, butane, hexane, and heptane. The blending ratio of the components in this composition is:
It varies depending on the type of blowing agent, the density and shape of the intended semi-rigid foam or foamed elastomer, but usually 0.1% of the total amount of ingredients.
Selected within the range of ~10% by weight.

The component catalyst may be any catalyst used in the production of conventional semi-rigid foam or foamed elastomers, including, for example, dibutyltin dilaurate, dibutyltin diacetate, and tetrabutyl dilauroyloxydistanoxane. , tetrabutyldiacetoxydistanoxane, dibutyltin malate butyl ester, and other tin compounds are preferably used. The blending ratio of the components in the composition of the present invention is usually 0.1 to 10% by weight based on the components.

Although the composition of the present invention is sufficiently non-yellowing per se, it is desirable to use an ultraviolet absorber to further enhance the non-yellowing property. Suitable UV absorbers include bis(2,2,6,6-tetramethyl-4-hydroxypiperidyl) sebacate, tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl) ) propionate] methane, 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole, etc. The amount of the ultraviolet absorber added is usually 2% by weight or less based on the composition of the present invention. Pigments, if necessary.
Fillers, foam stabilizers, and the like may be added in amounts conventionally used for that purpose.

The composition of the present invention is used in the form of a two-part composition consisting of a first component consisting of the following components, and a second component comprising other additives as necessary.
A semi-rigid foam or foamed elastomer can be produced by foaming and curing this by a conventionally known method.

When foaming and curing the composition of the present invention, in-mold foaming, particularly reaction injection molding (RIM) is preferably applied.

The semi-rigid foam or foamed elastomer obtained from the composition of the present invention has excellent weather resistance without yellowing even when exposed to direct sunlight, and also has excellent mechanical properties, such as automobile interior and exterior parts, furniture, etc.
It can be used for shoe soles, etc.

The invention will be illustrated below by way of examples. Note that parts and percentages are by weight unless otherwise specified. The starting materials in each example were processed using an injection device (high-pressure foamer) operating on the principle of countercurrent injection.

Example 1 Glycerin hepropylene oxide A polyether with a hydroxyl equivalent of 1600 and 80% primary end obtained by adding ethylene oxide to it, 83 parts, ethylene glycol 17 parts, tetra-n-butyl dilauroyloxydistanoxane (Formate TK- A consisting of 1.0 parts of IL, Tomi Pharmaceutical) and 2.0 parts of methylene chloride
Ingredients and dimethylcyclohexane diisocyanate (Takenate 600, manufactured by Takeda Pharmaceutical) and hydroxyl equivalent 105
B consisting of 96 parts of a prepolymer with an isocyanate content of 27.5% obtained by reacting a sucrose-based polyether of
The ingredients were mixed and poured into the mold. At this time, the temperature of the starting material was adjusted to 45°C, and the temperature of the mold was adjusted to 70°C.
In-mold time is 2 minutes. The resulting expanded elastomer test plate had the following physical properties.

Density (Kg/m ³ ) 965 Shore D hardness 46 Tensile strength (Kgf/cm ² ) 20℃ 180 60℃ 130 Tensile strength (Kgf/cm ² ) -30℃ 265 Elongation at break (%) 20℃ 160 60 ℃ 150 -30℃ 120 Sunshine type Weatherometer 400H irradiation△E
5.0 Example 2 Hydroxyl equivalent of 1650, obtained by adding propylene oxide and further ethylene oxide to diglycerin.
A component consisting of 85 parts of polyether with 80% primary terminals, 15 parts of ethylene glycol, 1.0 part of dibutyltin dilaurate, and 1.5 parts of methylene chloride;
An isocyanate group content of 27.0 obtained by reacting a polyether with a hydroxyl equivalent of 75 obtained by adding propylene oxide to glycerin and 4,4'-methylenebis(cyclohexyl isocyanate).
Component B consisting of 87.3 parts of prepolymer was mixed and foamed and cured to produce a foamed elastomer.
The physical properties are as follows.

Density (Kg/m ³ ) 980 Shore D hardness 48 Tensile strength (Kgf/cm ² ) 20℃ 170 60℃ 130 −30℃ 240 Elongation at break (%) 20℃ 165 60℃ 140 −30℃ 120 Sunshine type wafer Zaometer 400H△E 5.2 Comparative Example 1 Component A of Example 1 was mixed with component B' consisting of 98 parts of a prepolymer with an isocyanate content of 27.0% obtained by reacting carbodiimide-modified MDI with dipropylene glycol to obtain a material with a density of 1050. A foamed elastomer was obtained. This material turned yellow after 24-hour irradiation with the Sunshine Weatherometer.

Comparative Example 2 A component of Example 2 and a B' component consisting of 84.3 parts of a prepolymer with an isocyanate content of 28% obtained by reacting 4,4'-methylenebis(cyclohexyl isocyanate), H ₁₂ MDI, and dipropylene glycol. were mixed to obtain a foamed elastomer with a density of 1080. This material melted after 50 hours of Sunshine Weatherometer irradiation.

Comparative Example 3 Component B consisting of 84 parts of a prepolymer with an isocyanate content of 25% obtained by reacting a polyether with a hydroxyl equivalent of 200 obtained by adding propylene oxide to trimethylolpropane and 4,4'-methylenebis(cyclohexyl isocyanate). and 103 parts of component A of Example 2 were mixed to obtain a foamed elastomer having a density of 980. The mold could not be removed even 5 minutes after injection.

Comparative Example 4 Hydroxyl group equivalent obtained by adding propylene oxide and further ethylene oxide to glycerin
2000, 85 parts of polyether with 50% primary end, 15 parts of ethylene glycol, 1.0 part of Formate TK-IL,
Component A' consisting of 2.0 parts of methylene chloride and 84 parts of component B of Example 1 were mixed to obtain a foamed elastomer having a density of 1010. The mold was demolded 4 minutes after injection, but many serious cracks occurred due to bending.

Example 3 91 parts of the polyether with a hydroxyl equivalent of 1600 used in Example 1, 9 parts of ethylene glycol, 0.3 parts of water,
Component A' consisting of 1.0 part of Formate TK-IL and component B consisting of Example 1 and 61 parts of the prepolymer were mixed, and the molded product was demolded in 4 minutes to a thickness of 10 mm.
The physical properties of the obtained foam were as follows.

Density (Kg/m ³ ) 500 TISC Hardness 82 Tensile Strength (Kgf/cm ² ) 12 Elongation (%) 95 Tear Strength (Kgf/cm) 7 50% Compression Set (70℃×22H) 3 Sunshine Weather Meter 800H△E 7 Comparative Example 5 75 parts of the polyether with a hydroxyl equivalent of 1650 used in Example 2, 25 parts of a polyether with a hydroxyl equivalent of 110 obtained by adding ethylene oxide to trimethylolpropane, 0.3 part of water, Formate TK- IL
Component A consisting of 1.0 parts of methylene chloride and 2.0 parts of methylene chloride, and Component B consisting of 54 parts of a prepolymer with an isocyanate content of 25% obtained by reacting 4,4'-methylenebis(cyclohexyl isocyanate) and trimethylolpropane, A semi-rigid foam with a density of 550 was obtained. This material had low hardness at high temperatures and poor shape retention.

Claims (1)

[Claims] 1. A prepolymer with a free isocyanate group content of 35% or less, obtained by reacting an aliphatic or alicyclic polyisocyanate with a polyol having a hydroxyl equivalent of 150 or less and an average number of functional groups of 3 or more, with a primary terminal content of 60% or more, Polyols with an average number of functional groups of 3 or more and a hydroxyl equivalent of 1000 or more;
A composition for producing a semi-rigid foam or foamed elastomer with improved weather resistance and mechanical properties, comprising a polyhydroxy compound of 100 or less, a blowing agent and a catalyst.