JPH0370732B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyurethane, specifically a method for producing polyurethane that has high reactivity and self-release properties, and in particular, a method for producing polyurethane that has excellent reactivity and self-release properties when molded using the RIM method (reaction injection molding method). This paper relates to a method for producing polyurethane. Traditionally, RIM has been used as a means of manufacturing urethane molded products for applications such as automobile exterior and interior materials such as bumpers, instrument panels, and steering wheels.
The law is being put into practice. Urethane raw materials for RIM are required to have high reactivity and be able to be cured and demolded in a short time.
It is desired that the material has self-releasing properties and can be released from the mold without having to apply a mold release agent to the mold each time. The present inventors conducted studies to find raw material polyols and polyurethane manufacturing methods that satisfy these requirements. By using a specific polymer polyol, polyurethane molded products with high reactivity and self-releasing properties were produced. The present invention has been achieved based on the discovery that the present invention can be obtained. That is, the present invention provides a method for producing polyurethane by reacting an organic isocyanate with a high-molecular polyol or a low-molecular diol in the presence of a blowing agent if necessary, in which an ethylenically unsaturated monomer (a ) and a block polyoxyalkylene polyol (b) containing a terminal polyoxyethylene chain having a functional group number of 5 or more and an equivalent weight of 1450 or more, and the low molecular weight diol is (A) and (A). A method for producing a polyurethane having self-releasing properties, characterized in that polyol components consisting of a high molecular weight polyol (B) and a low molecular weight diol (C) are used in an amount of 4 to 25% based on the total weight. The block polyoxyalkylene polyol (b), which is a raw material for the polymer polyol (A) used in the present invention, is a compound having at least 5 (preferably 6 to 12) active hydrogen atoms (for example, a polyhydric Examples include compounds having a structure in which ethylene oxide and other alkylene oxides (alcohols, polyhydric phenols, amines) are added with blocks so as to form the terminal oxyethylene chain, and mixtures thereof. Examples of the polyhydric alcohol include sugar alcohols such as pentitol such as adonitol, arabitol, and xylitol; hexitol such as sorbitol, mannitol, iditol, talitol, and dulcitol; and sugars such as monosaccharides such as glucose, mannose, fructose, and sorbose, sucrose, and trehalose. , oligosaccharides such as lactose, raffinose; glycosides such as polyols (e.g. glycols such as ethylene glycol, propylene glycol, alkane polyols such as glycerin, trimethylolpropane, hexanetriol, pentaerythritol); poly(alkane polyols) such as triglycerin , polyglycerols such as tetraglycerin, polypentaerythritols such as dipentaerythritol and tripentaerythritol; and cycloalkane polyols such as tetrakis(hydroxymethyl)cyclohexanol. Examples of the polyhydric phenols include novolaks, such as the polyphenols described in US Pat. No. 3,265,641; and examples of amines include polyalkylene polyamines such as diethylenetriamine and triethylenetetramine. These active hydrogen atom-containing compounds are 2
More than one species may be used in combination. In addition, in a mixture of one or more of these compounds and a compound having 2 to 4 active hydrogen atoms (for example, those mentioned as raw materials for the polyether polyol in (B) below), Those having a number of 5 or more (preferably 6 to 12) can also be used. Preferred among these are polyhydric alcohols, especially sorbitol and sucrose. Another alkylene oxide (hereinafter abbreviated as AO) that is added to the above active hydrogen atom-containing compound together with ethylene oxide (hereinafter abbreviated as EO) is usually propylene oxide (hereinafter abbreviated as PO).
However, a small amount (for example, 5% or less) of other alkylene oxides (butylene oxide, styrene oxide, etc.) can also be used in combination with PO. The above block polyoxyalkylene polyol
As (b), EO is added to the above active hydrogen atom-containing compound.
and AO added in the order ()AO-EO (chipped), ()added in the order AO-EO-AO-EO (balanced), ()EO-
Examples include those added in the order AO-EO.
Among these, preferred are () and (). Equivalent weight of the above polyol (b) (molecular weight per OH)
is 1,450 or more, preferably 1,500 to 3,200, particularly preferably 1,600 to 3,000. If the equivalent weight is lower than 1450, the physical properties such as temperature characteristics and elongation of the resulting polyurethane will deteriorate. If the equivalent weight exceeds 3,200, the viscosity increases, flowability deteriorates, and reactivity decreases, which is not preferable. (b) Terminal polyoxyethylene chain content (hereinafter referred to as terminal
EO amount (abbreviated as EO amount) is usually 10% (weight%, same below)
or more, preferably 12% to 30%, more preferably
It is 15-28%. If the amount of terminal EO is less than 10%, the reactivity is low, the curing property and initial physical properties are low, and it is impossible to mold a polyurethane that has self-releasing properties, and particularly when molding by the RIM method, a satisfactory effect cannot be obtained. do not have. In addition, if the amount of terminal EO exceeds 30%, the curing properties will improve, but the viscosity will increase and it will become cloudy at a temperature slightly lower than room temperature, resulting in poor workability, and physical properties such as temperature characteristics and water absorption will deteriorate. Undesirable. In addition, even if the terminal EO amount is less than 10%, it can be combined with a terminal EO amount of 10% or more, or if the terminal EO amount exceeds 30%, it can be combined with a terminal EO amount of 30 or less (average).
They can be used by blending so that the amount of terminal EO falls within the above range. In addition, the total polyoxyethylene chain content (hereinafter abbreviated as total EO amount) of (b) is usually 10% or more, preferably 12~
It is 30%. Examples of the ethylenically unsaturated monomer (b) used in the production of the polymer polyol (A) used in the present invention include the following: () Acrylic acid, methacrylic acid and derivatives thereof: acrylonitrile, meth Acrylonitrile, acrylic acid, methacrylic acid and their salts, methyl acrylate, methyl methacrylate,
Dimethylaminoethyl methacrylate, acrylic amide, methacrylic amide, etc. () Aromatic vinyl monomers: styrene, α-methylstyrene, etc. () Olefin hydrocarbon monomer: ethylene,
Propylene, butadiene, isobutylene, isoprene, 1,4-pentadiene, etc. () Vinyl ester monomer: vinyl acetate, etc. () Vinyl halide monomers: vinyl chloride, vinylitene chloride, etc. () Vinyl ether monomer: vinyl methyl ether, etc. Among these, preferred are acrylonitrile, methyl methacrylate, styrene, and butadiene. Particularly preferred is acrylonitrile, a combination of acrylonitrile and styrene (styrene:acrylonitrile weight ratio 10:90 to 60:40)
It is. The above-mentioned polyol (b) may be used in combination with other polyols (for example, high-molecular polyols and/or low-molecular polyols listed as examples of (B) and (C) below) to produce a polymer polyol, if necessary. In this case, the amount of (b) in the total amount of polyol is usually 20%
The amount of low molecular weight polyol is preferably 50% or more, and the amount of low molecular weight polyol is usually 20% or less. The proportions of polyol ((b) and other polyols as necessary) and monomers in polymer polyol (A) can be varied over a wide range, but usually the ethylenically unsaturated monomer is used per 100 parts by weight of polyol. (or polymer) from 2 to 70 parts by weight, preferably from 5 to 40 parts by weight. The production of polymer polyols from polyols and ethylenically unsaturated monomers can be carried out by conventional methods. For example, a method of polymerizing an ethylenically unsaturated monomer in a polyol in the presence of a polymerization catalyst (radical generator, etc.) 50
-15894) or a method in which a polymer obtained by prepolymerizing the above monomers and a polyol are graft-polymerized in the presence of a radical generator (Japanese Patent Publication No. 15894-
47597). The former method is preferred. As the polymerization catalyst (radical generator) used in the polymerization reaction, azo compounds, peroxides, persulfates, perborates, etc. can be used, but azo compounds are preferred in practical terms. The amount used is not particularly limited, and is, for example, 0.1 to 20 parts by weight, preferably 0.1 to 15 parts by weight, per 100 parts by weight of the ethylenically unsaturated monomer (or polymer). The above polymerization can also be carried out in the presence of a solvent such as toluene, xylene and the like. The reaction temperature is usually 50-170°C, preferably 90-150°C. In carrying out the method for producing polyurethane of the present invention, the polymer polyol (A) is used alone or in combination with another polymer polyol (B) or/and a low molecular weight active hydrogen-containing compound (C) to produce an organic This can be done by reacting with polyisocyanate.
Other polymer polyols (B) that may be used in combination include polyether polyols, polyester polyols, and other polymer polyols. As polyether polyols, the above
(b); and polyether polyols other than (b), such as compounds having 2 to 4 active hydrogen atoms (low-functional polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl Glycol, dihydric alcohol such as 1,6-hexanediol, trihydric alcohol such as glycerin, trimethylolpropane, hexanetriol, triethanolamine, pentaerythryl,
alkylene oxide (EO and/or AO such as PO) adducts of tetrahydric alcohols such as methyl glucoside; polyhydric phenols such as hydroquinone, bisphenol A; amines such as ethylenediamine, aminoethylpiperazine, etc.;
Low-functionality polyether polyols such as polytetramethylene ether glycol; polyether polyols with a functional group number of 5 or more, having terminal polyoxyethylene chains and internal random poly(oxyethylene/oxypropylene) chains, terminal polyoxyethylene chains Examples include those with no chains (less than 10%) (PO adducts, PO/EO random adducts, PO/EO block adducts with polyoxyethylene chains only inside), or those with an equivalent weight of less than 1450. It will be done. As the polyester polyol, the above-mentioned low-functional polyhydric alcohol (a dihydric alcohol such as ethylene glycol and diethylene glycol, or a mixture of this and a trihydric alcohol such as glycerin and trimethylolpropane) and/or the above-mentioned low-functional polyether polyol is used. , reacting (condensing) polycarboxylic acids (e.g., adipic acid, maleic acid, phthalic acid, etc.) or their anhydrides with alkylene oxides (EO, PO, etc.), or ring-opening polymerization of lactones (e.g., ε-caprolactone). Examples include those obtained by Other polymer polyols include polyols obtained by polymerizing polyols other than (b) such as polyether polyols and/or polyester polyols with ethylenically unsaturated monomers (acrylonitrile, styrene, etc.) No. 54-101899, Japanese Patent Publication No. 1983-
122396). Among (B), preferred are low-functionality polyether polyols [especially those having terminal polyoxyethylene chains (diols and/or triols, terminal EO content 10 to 30%)] and polymer polyols thereof. The amount of (A) in the total amount of the polymer polyol [(A) and optionally (B)] is usually 20% or more, preferably 30% or more, and more preferably 40% or more. If (A) is less than 20%, a polyurethane with good curing properties, initial physical properties and self-releasing properties cannot be obtained. Also, polymer polyol [(A) and if necessary
The ratio of (b) [(b) in (A) and (b) added if necessary] to the polymer polyol part (excluding the polymer part) in (B)] is usually 20% or more. , preferably 30% or more, more preferably 40% or more. The terminal EO content of the entire polymer polyol is usually 10
% or more, preferably 12 to 30%, more preferably 15%
~28%. The equivalent weight (average) of the entire polymeric polyol is usually 1,450 to 3,000, preferably 1,600 to 2,800. As the low molecular diol compound (C) used in the present invention, chain extenders such as low molecular diols, diamines, amino alcohols, etc. can be used. Low molecular weight diols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, neopentyl glycol, hexanediol, molecular weight 200-400.
polyethylene glycol and polypropylene glycol, and low-molecular-weight diols having a cyclic group (for example, those described in Japanese Patent Publication No. 1474/1983; propylene oxide adduct of bisphenol A, etc.). By using a chain extender in combination, the amount of heat generated during the reaction with the isocyanate becomes larger, thereby improving the curing property. In addition to the flexibility possessed by polymeric polyols, the hardness increases due to the increased concentration of urethane bonds (or urea bonds) in the molded product, resulting in a molded product with high physical properties that has a good balance of rigidity and flexibility. can get. The amount of (C) used (including the amount of low-molecular-weight polyol if it is contained in the polymer polyol; the same applies hereinafter) can be varied depending on the required performance (rigidity, etc.). In the case of low-molecular diols, it is usually 30% or less, preferably 4 to 25% of the total polyol.
amount used. When a diamine is used, it is used in a smaller amount than the above, for example, 10% or less, preferably 1 to 8%, based on the total amount of polyol and amine. If the amount of the chain extender is greater than the above, the urethane becomes too rigid, resulting in a decrease in initial strength, elongation, and impact properties. The molar ratio of the polymer polyol to the chain extender is usually 1:20 to 160, preferably 1:25 to 140. (C) is a chain extender, and together with it, a crosslinking agent such as trivalent or higher polyol such as glycerin, trimethylolpropane, triethanolamine, tris or tetrakis(hydroxypropyl)ethylenediaminediethyldiaminotoluene may be used. You can also do it. The use of crosslinking agents increases the viscosity of the reaction system, reduces the flowability during injection into the mold, reduces the elongation of the physical properties of the molded product, and increases the hardness, so it is preferable not to use them.If used, use a small amount and adjust the amount of chain extender. It is preferable that the amount is 20% or less. Total active hydrogen components [(A) and (C), if necessary (B)]
The average equivalent weight is usually 120 to 1000, preferably 140 to
It is 900. As the organic polyisocyanate used in the present invention, those conventionally used in the production of polyurethane can be used. For example, aliphatic polyisocyanates (hexamethylene diisocyanate,
lysine diisocyanate, etc.), alicyclic polyisocyanates (hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, etc.), aromatic polyisocyanates [toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthylene diisocyanate, etc. isocyanate, xylylene diisocyanate, etc.] and mixtures thereof. Among these, preferred are aromatic diisocyanates, particularly preferred are TDI,
It is MDI. These polyisocyanates are crude polyisocyanates, such as crude TDI, crude
Phosgenated product of MDI [crude diaminophenylmethane {condensation product of formaldehyde and aromatic amine or mixture thereof; mixture of diaminodiphenylmethane and a small amount (e.g. 5 to 20% by weight) of trifunctional or higher functional polyamine} : Polyallyl polyisocyanate (PAPI)] or modified polyisocyanate such as liquid MDI (carbodiimide modification, trihydrocarbyl phosphate modification, etc.)
or excess polyisocyanate (TDI, MDI, etc.)
It can also be used as a free isocyanate-containing prepolymer obtained by reacting polyisocyanate with a polyol, or they can be used in combination (for example, a modified polyisocyanate and a prepolymer are used together). Polyols used in the production of the above prepolymer include polyols having an equivalent weight of 30 to 200, such as glycols such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; triols such as trimethylolpropane and glycerin; and high-functionality polyols such as pentaerythritol and sorbitol. and alkylene oxide (ethylene oxide and/or propylene oxide) adducts thereof. Among these, those having 2 to 3 functional groups are preferred. The content of free isocyanate groups in the above-mentioned modified polyisocyanates and prepolymers is generally 10-33%, preferably 15-30%, particularly preferably 20-29%. When producing polyurethane using the polymer polyol (A) according to the present invention, it may be foamed to produce polyurethane foam, or polyurethane resin (elastomer, sheet) may be produced without foaming.
may be manufactured. In the former case, the total density of the polyurethane (foam) produced is usually 0.3 g/cm ³ or more,
Preferably 0.5 g/cm ³ or more, particularly preferably 0.8 g/cm 3 or more
It is preferable to carry out foaming so that the foam size is at least cm ³ .
If the total density is lower than 0.3 g/cm ³ , a polyurethane resin with excellent self-releasing properties cannot be produced. Foaming is usually carried out using a foaming agent, but foaming can also be carried out by introducing a gas such as air during molding (air loading). As the blowing agent, water and/or a halogen-substituted aliphatic hydrocarbon blowing agent (fluorocarbons such as trichloromonofluoromethane) can be used. The amount of water used is usually 0.4% or less, preferably 0.2% or less, based on the polymer polyol (polyether polyol). If the amount of water used exceeds 0.4%, carbon dioxide gas generated by the reaction will be exposed to the surface as bubbles, damaging the appearance of the molded product. In addition, in terms of physical properties, the increase in urea bonds increases hardness, which is undesirable, as it increases brittleness especially at low temperatures. The amount of the halogen-substituted hydrocarbon blowing agent used is usually 30% or less (preferably 2 to 2%) based on the weight of the resin raw materials (total of organic polyisocyanate, polymeric polyol, chain extender, and crosslinking agent) when water is not used. 20%), and when 0.4% water is used in conjunction with the polymer polyol, it is usually less than 20% (especially 0 to 15%) based on the weight of the resin raw material.
is preferred. The ratio of polyisocyanate and active hydrogen atom-containing compound (polymer polyol, chain extender, crosslinking agent, water) may be the same as that of ordinary polyurethane (resin, foam) (for example, 95 as an NCO index).
~120 especially 100-110). Also, excessive amounts of isocyanate (for example, 120 to 1000 as an index, especially 150
~500) can also be used to form polyisocyanurates (resins, foams). Further, if necessary, the reaction can be carried out in the presence of a catalyst (tertiary amines, organic tin compounds, organic lead compounds, etc.), surfactants (silicone surfactants, etc.), and other auxiliaries. If necessary, pigments, fillers, flame retardants, solvents, internal mold release agents, thixotropic agents, etc. may be added. The polyurethane manufacturing method may be the same as conventional methods, and either the one shot method or the prepolymer method (quasi-prepolymer method) can be applied. The polyurethane manufacturing method of the present invention is particularly useful for molding by the RIM method, but can also be applied to other methods such as injection molding using a low-pressure foaming machine, spraying method, etc. Further, a method for producing a polyurethane molded article by molding by the RIM method can be carried out by a conventional method. For example, a polyol, a chain extender, a crosslinking agent, a catalyst, and if necessary a blowing agent (water and/or fluorocarbons), a pigment, and a foaming agent are added and mixed uniformly to form a liquid A, and a liquid B is an organic isocyanate prepared in advance. Prepare and fill tanks A and B of the high-pressure foaming machine. The injection nozzle of the high-pressure foaming machine and the injection port of the mold are connected in advance, and liquids A and B are mixed with a mixing head and poured into a closed mold, and after hardening, the mold is demolded. According to the present invention, a block polyoxyalkylene polyol containing an ethylenically unsaturated monomer (a) and a terminal polyoxyethylene chain having a functional group number of 5 or more and an equivalent weight of 1450 or more as at least a part of the polyol.
By reacting with an organic polyisocyanate using the polymer polyol (A) and low-molecular diol from (b), the curing property is fast, the self-releasing property is excellent, and the strength of the resin is greatly improved. A polyurethane with excellent initial strength can be obtained. Furthermore, the polymer polyol has excellent curing properties and requires only a small amount of catalyst, thereby avoiding deterioration in physical properties and heat resistance of polyurethane due to the use of a large amount of catalyst. Furthermore, since the polymer polyol is easily rigid, it requires less chain extender than when using a polyether polyol, which prevents a decrease in the elongation of the molded product, and eliminates the need for expensive isocyanates. The amount used can be reduced. Furthermore, since the amount of chain extender can be reduced, the concentration of urethane groups that have adhesive strength with metals etc. is relatively reduced, which has the advantage of further enhancing the self-releasing effect. Furthermore, in the case of painting polyurethane molded products, molded products that use a large amount of catalyst to speed up curing have the disadvantage that the paint color changes over time.According to the present invention, this problem can be solved. Does not occur. In addition, in the present invention, by using a chain extender in combination with the polyol (A), the urethane bond concentration becomes higher than when it is not used in combination, so the calorific value is further increased, the initial strength is increased, and the curing property is further improved. It also improves curing properties while keeping the viscosity of the urethane reactant low, and
It has excellent effects in terms of a good balance between elongation and hardness in the physical properties of molded products. The present invention, in which the polymer polyol (A) and organic polyisocyanate are reacted and molded by the RIM method, is superior to conventional methods in the following points: () Excellent curing properties It is extremely effective in shortening the cycle time from injection to demolding, which is the original purpose of the RIM method. () Even with a small amount of catalyst, it has excellent curing properties, so the increase in viscosity when reacted with polyisocyanate is moderate, and it is possible to avoid insufficient filling and the formation of voids that occur in molded products due to poor flowability. () Conventional methods for increasing curing properties require a large amount of catalyst, resulting in a significant deterioration of the physical properties of the molded product over time, whereas the RIM method of the present invention requires only a small amount of catalyst. Problems such as deterioration of physical properties of the product and discoloration of painted molded products do not occur. () Even with a small amount of catalyst, the curing property is excellent, so the viscosity increase is moderate when reacting with polyisocyanate, but it quickly reaches the cream state, which is the state before reaction curing, so it is difficult to cure in the mold. When flowing, the urethane flows and hardens without penetrating the uneven surfaces on the mold surface, so the adhesion between the mold surface and the urethane is weak, and the resistance during demolding is extremely small, making it difficult to use external mold release agents. It has self-releasing properties that allow it to be released from the mold 5 or more times, especially 10 to 20 times, once sprayed. Furthermore, the method of the present invention can be applied to various polyurethane manufacturing methods (foam, elastomer,
It exhibits excellent effects particularly in polyurethane manufacturing methods that conventionally required relatively large amounts of catalysts (sheets, etc.) and polyurethane manufacturing methods that use chain extenders. The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. (The parts shown in the Examples represent parts by weight.) The components used in the Examples and Comparative Examples below are as follows. Polyol: 182 parts of sorbitol, 9418 parts of propylene oxide, then ethylene oxide
100 parts of a polyether polyol with an OH number of 28 obtained by adding 2400 parts of the monomer, and 10 parts of acrylonitrile and 10 parts of styrene as ethylenically unsaturated monomers were mixed together at a temperature of 125 to 135°C.
Reacted with 1.0 part of azobisisobutyronitrile as an initiator. Polyol: 92 parts of glycerin and 228 parts of sucrose are mixed to give an average number of functional groups of 5, 6115 parts of propylene oxide and 1815 parts of ethylene oxide.
A monomer prepared by pre-mixing 100 parts of a polyether polyol with an OH value of 34 obtained by adding 100 parts with 8 parts of acrylonitrile and 2 parts of styrene as ethylenically unsaturated monomers was heated at a temperature of 125 to 135°C.
Reacted with 0.5 part of asoisobutyronitrile as an initiator. Polyol: 342 parts of sucrose, 13,400 parts of propylene oxide, then 1027 parts of ethylene oxide,
OH value obtained by further adding 1027 parts of propylene oxide, followed by 2154 parts of ethylene oxide
25 polyether polyol and 25 parts of acrylonitrile as ethylenically unsaturated monomer.
Reacted at a temperature of 125-135°C with 1.0 part of azobisisobutyronitrile as an initiator. Polyol: Novolak 622 with an average functional group number of 6
100 parts of a polyether polyol with an OH value of 30 obtained by adding 7800 parts of propylene oxide and 2800 parts of ethylene oxide to 125 parts of acrylonitrile as an ethylenically unsaturated monomer.
Reacted at a temperature of ~130°C with 1.0 part of azoisobutyronitrile as an initiator. Polyol: 146 parts of triethylenetetramine to 9,841 parts of propylene oxide, then 7:3 of propylene oxide and ethylene oxide
(Weight ratio) A monomer prepared by pre-mixing 100 parts of a polyether polyol with an OH value of 24 obtained by adding 2333 parts of the mixture and 1680 parts of ethylene oxide, and 10 parts of acrylonitrile and 10 parts of styrene as ethylenically unsaturated monomers. reacted with 1.0 part of azobisisobutyronitrile as an initiator at a temperature of 125-135°C. Polyol: 21,000 parts of polyether polyol obtained by adding 18,726 parts of propylene oxide to 182 parts of sorbitol and then 2,100 parts of ethylene oxide were reacted with 774 parts of trimellitic anhydride, and then 2,400 parts of ethylene oxide were reacted. Polyol 100 with 12 functional and OH value 28
and 13 parts of acrylonitrile as an ethylenically unsaturated monomer were reacted at a temperature of 125 to 135°C with 0.5 part of azobisisobutylnitrile as an initiator. Polyol A: 92 parts of glycerin, 4908 parts of propylene oxide, then 2000 parts of ethylene oxide
100 parts of a polyether polyol with an OH value of 24 obtained by adding 25 parts of acrylonitrile as an ethylenically unsaturated monomer at a temperature of 125 to 135°C.
Reacted with 1.0 part of azobisisobutyronitrile as an initiator. Polyol B: 4,660 parts of propylene oxide to 136 parts of pentaerythritol, then 1,200 parts of a 1:1 (weight ratio) mixture of propylene oxide and ethylene oxide, and then 1,500 parts of ethylene oxide with an OH value of 30. 125 parts of a monomer prepared by pre-mixing 100 parts of polyether polyol, 12.5 parts of acrylonitrile and 12.5 parts of styrene as ethylenically unsaturated monomers.
Reacted at a temperature of ~135°C with 1.0 part of azobisisobutyronitrile as an initiator. Polyol C: 100 parts of a polyether polyol with an OH value of 28 obtained by adding 3124 parts of propylene oxide to 76 parts of propylene glycol and then 800 parts of ethylene oxide, 20 parts of acrylonitrile as ethylenically unsaturated monomers, and 5 parts of styrene.
1.0 part of azobisisobutyronitrile as an initiator and reacted with 1.0 part of azobisisobutyronitrile at a temperature of 125 to 135°C. Polyol D: 92 parts of glycerin, 4908 parts of propylene oxide, then 2000 parts of ethylene oxide
A polyether polyol with an OH value of 24 obtained by adding Polyol E: A polyether polyol with an OH value of 28 obtained by adding 3124 parts of propylene oxide to 76 parts of propylene glycol and then 800 parts of ethylene oxide. Polyol F: A polyether polyol with an OH value of 47 obtained by adding 1,600 parts of propylene oxide and then 700 parts of ethylene oxide to 76 parts of propylene glycol. DABCO 33LV: Sankyo Air Amine catalyst manufactured by Products. DABCO DC-2: Catalyst manufactured by Sankyo Air Products. DBTDL: Dibutyltin dilaurate omelette UL-28: Tin catalyst handled by Kasei Appdition Co., Ltd. Sumidyur PC: Modified MDI Millionate manufactured by Sumitomo Bayer Urethane Co., Ltd. MTL: Coronate CE-141: } Modified MDI manufactured by Nippon Polyurethane Co., Ltd. Resilient agent B-511: External mold release agent manufactured by Chukyo Yushi Co., Ltd. (Tables 2, 4 and 6 molding Table 1 shows the appearance and analytical values of the above polyol.

〔Molding condition〕

Discharge amount: approx. 20-40Kg/min Discharge pressure (A/B) (Kg/ ^cm2G ): 160/150 Injection time: approx. 1.5-2.2 seconds Raw material temperature (both A and B): approx. 40℃ Mold temperature: about 70°C Isocyanate index: 105 The molding recipe and physical properties of the obtained high-density polyurethane are shown in Tables 2 to 7. The molded polyurethane was left to stand under the following conditions and then measured. The molded products in Tables 3 and 5 are heated at 120℃ after release from the mold.
After annealing for 30 minutes, it was left at 25°C x 60% RH for 3 days or more and then measured. The molded products in Table 7 are heated at 25℃ after release from the mold.
Measurements were taken after being left at 60% RH for more than one week. (Note) The mold release time and physical properties are as follows. Mold release time: The time from the start of injection of the reaction liquid into the mold until it is taken out. Initial strength -: The time from the start of injection until the end of the molded product is bent 180 degrees immediately after the molded product is removed from the mold and no cracks are formed (seconds). ). Initial strength: Immediately after the molded product is removed from the mold, it is punched out using a No. 1 dumbbell to create a sample for tensile strength measurement. Next, the tensile strength of this sample was measured 60 seconds after release from the mold, and this was taken as the initial strength. Number of self-release times: After applying an external mold release agent to a mold once, the number of times continuous molding is performed to obtain mold release properties similar to those obtained during application. As molds, flat plate molds and actual molds (in Tables 2 and 4, molds for producing passenger car bumpers, and in Table 5, molds for producing passenger car handles) were used. 50% - Modulus tensile strength elongation: Dumbbell No. 2, Crosshead speed 50mm/split Tear strength: Dumbbell type B, Crosshead speed
50mm/min Bending modulus: Sample 25 x 125 x 2.5mm Span 40mm Loading nose 5R Crosshead speed 10mm/min Chart speed 100mm/min Heat sag: Sample 25 x 125 x 2.5mm 120℃ with the above sample overhanged by 100mm After leaving it for 1 hour, cool it down at room temperature for 30 minutes and measure the distance it sagged. Brittle temperature: According to JIS K-6301.

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Claims (1)

[Claims] 1. A method for producing polyurethane by reacting an organic isocyanate with a high-molecular polyol and a low-molecular diol in the presence of a blowing agent if necessary,
As at least a part of the polyol, a polymer polyol (A ), and low molecular weight diols are (A) and
Based on the total weight of polyol components consisting of high molecular polyol (B) and low molecular diol (C) other than (A)
A method for producing polyurethane with self-releasing properties, characterized by using 25%. 2 (A) at 20% based on the weight of the polymeric polyol
The manufacturing method according to claim 1, wherein the above amount is used. Claim 1 or 2, wherein the terminal polyoxyethylene chain content of 3(b) is 10% by weight or more.
Manufacturing method described in section. 4. The method according to claim 1, 2 or 3, wherein the polyoxyethylene chain content of (b) is 10 to 30% by weight. 5. The manufacturing method according to any one of claims 1 to 4, wherein (B) is a terminal polyoxyethylene chain-containing diol and/or triol. 6 Add the foaming agent to polyurethane whose total density is 0.5 g/cm ³
The manufacturing method according to any one of claims 1 to 5, wherein the above amount is used.