JPH055848B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing highly elastic polyurethane foam. [Prior Art] Conventionally, as a method for producing highly elastic polyurethane foam, an organic polyisocyanate and a polyurethane foam having a functional group number of 3 have been used.
Alternatively, a method is known in which a polymeric polyol having a relatively large molecular weight and a high ethylene oxide content (4) is reacted in the presence of a catalyst, a blowing agent, a foam stabilizer, and if necessary a crosslinking agent and additives. [Problems to be Solved by the Invention] However, in this method of manufacturing polyurethane foam, there is a limit to the rebound resilience, which is a feature of high elasticity polyurethane foam. [Means for Solving the Problems] The present inventors have conducted repeated studies on a method for manufacturing a highly elastic polyurethane foam that can further improve rebound properties, and as a result, have arrived at the present invention.
That is, the present invention provides a method for producing a polyurethane foam by reacting an organic polyisocyanate and a polymeric polyol in the presence of a catalyst, a blowing agent, a foam stabilizer, and, if necessary, a crosslinking agent and additives. Based on the weight of (A), the polyol has a functional group number of 3 and a hydroxyl value of 22 to 35 at the end.
Polyol (A) containing ~25% polyoxyethylene chains and 5-25% polyoxyethylene chains based on the weight of (B) at the end with a functional group count of 4 and a hydroxyl value of 22-40 It consists of a polyol (B) that
A method for producing a highly elastic polyurethane foam characterized by using a polyol having a weight ratio of (A)/(B) of 38/62 to 90/10, wherein at least a portion of (A) is an ethylenically unsaturated monomer. 2. The method according to claim 1, wherein the compound (B) is modified with an ethylenically unsaturated monomer. The polyol (A) used in the present invention includes compounds having a functional group number of 3 and three active hydrogen atoms (for example, alcohols, compounds having a structure in which alkylene oxide is added to amines, and mixtures thereof). Examples of alcohols include trihydric alcohols such as glycerin, trimethylolpropane, trimethylolethane, and hexanetriol; examples of amines include ammonia, alkanolamines such as mono-, di-, and tri-ethanolamine, isopropanolamine, and aminoethylethanolamine. and heterocyclic amines such as aminoethylpiperazine.Two or more of these active hydrogen atom-containing compounds may be used in combination.Among these, alcohols are preferred.The above active hydrogen Examples of alkylene oxides added to atom-containing compounds include ethylene oxide (hereinafter abbreviated as EO) and propylene oxide (hereinafter abbreviated as EO).
abbreviated as PO) 1,2-, 1,3-, 1,4-, 2,
Examples include 3-butylene oxide, styrene oxide, etc., and combinations of two or more of these, preferably EO, PO, and a combination of EO and PO.
Addition formats when used in combination include block and/or random addition, and preferred are (1) block addition in the order of PO-EO;
(2) Blocks added in the order PO-EO-PO-EO, (3) Blocks added in the order EO-PO-EO, (4) PO and EO randomly added, (5), This is a block addition in the order of random adduct-EO of (4). These may be used in combination. The hydroxyl value of the polyol (A) used in the present invention is from 22 to
35, preferably 23-33, particularly preferably 24-31. If the hydroxyl value is less than 22, the hardness of the foam and compression set will be significantly lowered, and if it exceeds 35, the rebound resilience, which is the object of the present invention, will be significantly lowered and the foam will tend to form a hollow foam. The amount of EO in polyol (A) is 5 to 25%, preferably 10 to 25%.
18%, particularly preferably 14-16%. terminal EO
If the amount of EO is less than 5%, molding defects such as collapse will occur in the foam, and if the terminal EO amount exceeds 25%, molding defects such as porosity will occur in the foam. Examples of the polyol (B) used in the present invention include compounds having a structure in which an alkylene oxide is added to a compound having 4 functional groups and 4 active hydrogen atoms (for example, alcohols and amines), and mixtures thereof. It will be done. Examples of alcohols include tetrahydric alcohols such as pentaerythritol, methyl glucoside, and diglycerin, and examples of amines include alkylene diamines such as ethylenediamine, propylene diamine, and hexamethylene diamine. Two or more of these active hydrogen atom-containing compounds may be used in combination. Among these, alcohols are preferred. The alkylene oxide to be added to the above active hydrogen atom-containing compound is a polyol.
The same thing as explained in (A) can be used, and the same addition format can also be used. The hydroxyl value of the polyol (B) used in the present invention is from 22 to
40, preferably 25-37, particularly preferably 28-35. If the hydroxyl value is less than 22, the hardness of the foam and compression set will be significantly lowered, and if the hydroxyl value exceeds 40, the rebound resilience, which is the object of the present invention, will be significantly lowered and the foam will tend to form an air-filled foam. The amount of terminal EO in the polyol (B) is 5 to 25%, preferably 8 to 18%, particularly preferably 10 to 14%. If the amount of terminal EO is less than 5%, molding defects such as collapse will occur in the foam, and if the amount of terminal EO is less than 5%,
If it exceeds this, molding defects such as air bubbles will occur in the foam. The weight ratio of polyol (A)/polyol (B) is 38/62 to 90/10, preferably 43/57 to 85/15,
Particularly preferably 50/50 to 80/20. When the weight ratio of (A) is less than 38 or greater than 90, or when the weight ratio of (B) is less than 10 or greater than 62, the rebound when formed into a foam does not improve. In the present invention, polyol (A) and polyol
(B) may be at least partially modified with an ethylenically unsaturated monomer. It may also be a so-called polymer polyol. Monomers used in the production of polymer polyols include: (i) Acrylic acid, methacrylic acid and derivatives thereof: acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid and their salts, acrylic acid Methyl, methyl methacrylate,
Dimethylaminoethyl methacrylate, acrylic amide, methacrylic amide, etc. (ii) Aromatic vinyl monomers: styrene, α-methylstyrene, etc. (iii) Olefinic hydrocarbon monomers: ethylene, propylene, butadiene, isobutylene, isobrene, 1,4-pentadiene, etc. (iv) Vinyl ester monomers: vinyl acetate, etc. (v) Vinyl halide monomers: vinyl chloride, vinylidene chloride, etc. (vi) Vinyl ether monomers: vinyl methyl ether, etc. Among these, preferred are acrylonitrile, methyl methacrylate, styrene, and butadiene. Particularly preferred are acrylonitrile,
Combination of acrylonitrile and styrene (styrene:
The weight ratio of acrylonitrile is 5:95 to 95:5). When using a trifunctional polyol and a tetrafunctional polyol that have both been modified, a trifunctional unmodified polyol and a tetrafunctional unmodified polyol may be mixed and modified; The polyol may be mixed with a tetrafunctional modified polyol. The proportion of monomers used for modification can be varied over a wide range, but usually, based on 100 parts by weight of polyol [polyol (A), polyol (B), and a mixture of polyol (A) and polyol (B)], The ethylenically unsaturated monomer (or polymer) is usually 2 to 100
Parts by weight, preferably 2 to 80 parts by weight, particularly preferably 2 to 55 parts by weight. Modification of a polyol with an ethylenically unsaturated monomer (production of a polymer polyol) can be carried out by a conventional method. For example, a method in which an ethylenically unsaturated monomer is polymerized in a polyol in the presence of a polymerization catalyst (such as a radical generator) (U.S. Patent No.
No. 3383351, Special Publication No. 39-24787, Special Publication No. 47-
47999, JP-A-50-15894) and a method in which a polymer obtained by pre-polymerizing the above monomers and a polyol are graft-polymerized in the presence of a radical generator (Japanese Patent Publication No. 47-47597). . 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 and peroxides are preferred in practice. The amount used is also 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 using solvents such as toluene,
It can also be carried out in the presence of xylene or the like. The reaction temperature is usually 50-170°C, preferably 90-150°C. When polyol (A) and polyol (B) are not modified with an ethylenically unsaturated monomer, the hydroxyl value of polyol (A) is 22 to 35, preferably 23 to 33, particularly preferably 24 to 31, or The hydroxyl value of the polyol (B) is 22 to 40, preferably 25 to 37, particularly preferably 28 to 35, but at least a part of the polyol (A) and polyol (B) is an ethylenically unsaturated monomer. When modified, the hydroxyl value of the modified polyol (A) is usually 11 to 34, preferably 12 to 32, particularly preferably 14 to 30, and the hydroxyl value of the modified polyol (B) is usually 11 to 39, preferably is 12-36, particularly preferably 14-34. In addition, when at least a part of polyol (A) and polyol (B) is modified with an ethylenically unsaturated monomer, modified polyol (A)/modified polyol
The weight ratio of (B) is the same as in the unmodified case, 38/
62-90/10, preferably 43/57-85/15, particularly preferably 50/50-80/20. (In this case, the weight ratio was determined by excluding the weight of acrylonitrile and the polyol obtained by polymerizing acrylonitrile and an ethylenically unsaturated monomer such as styrene.) Conventional organic polyisocyanates used in the present invention Those used in the production of polyurethane can be used. Such polyisocyanates include aromatic polyisocyanates having 6 to 20 carbon atoms (excluding the carbon in the NCO group), such as 2,4- and/or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4'- and/or 4,4'-diphenylmethane diisocyanate (MDI) Crude MDI [crude diaminophenylmethane {condensation product of formaldehyde with aromatic amines (aniline) or mixtures thereof: diaminodiphenyl Methane and a small amount (e.g. 5-20
(% by weight) of a mixture with a trifunctional or higher functional polyamine}
phosgenates such as polyallyl polyisocyanate (PAPI); aliphatic polyisocyanates having 2 to 18 carbon atoms (e.g. hexamethylene diisocyanate, lysine diisocyanate, etc.); alicyclic polyisocyanates having 4 to 15 carbon atoms (e.g. isophorone diisocyanate); , dicyclohexylmethane diisocyanate); aromatic aliphatic polyisocyanates having 8 to 15 carbon atoms (for example, xylylene diisocyanate); and modified products of these polyisocyanates (urethane group, carbodiimide group, allophanate group, urea group, Biuret group, uretdione); polyisocyanates other than those described in Japanese Patent Application No. 59-199160; and mixtures of two or more of these. Among these,
Commercially readily available polyisocyanates include, for example, 2,4- and 2,6-TDI, and mixtures of these isomers, PAPI, also called crude MDI, and urethane groups derived from these polyisocyanates, carbodiimides. They are modified polyisocyanates containing a group, an allophanate group, a urea group, a biuret group, and an isocyanurate group. Catalysts used in the present invention include catalysts commonly used in polyurethane reactions, such as amine catalysts (tertiary amines such as triethylenediamine and N-ethylmorpholine), tin catalysts (stannous octylate, dibutyltin dilaurate), etc.), other metal catalysts (such as lead octylate) can be used. As the blowing agent, for example, water, monofluorotrichloromethane, methylene chloride, etc. can be used. Examples of foam stabilizers include silicone surfactants (polysiloxane-polyoxyalkylene copolymers). Examples of crosslinking agents that may be used as necessary include polyhydric alcohols, and polyhydric alcohols with a small amount of alkylene oxide added as described for polyol (A) [diethylene glycol, glycerin, glycerin with EO added (molecular weight
600), EO added to rilbitol (molecular weight 800, etc.), amines and amines added with a small amount of alkylene oxide as described for polyol (A) [diethanolamine, triethanolamine, triethanolamine with EO added, etc. (molecular weight 600), PO to ethylenediamine
EO added (molecular weight 800, etc.) can be used. These may be used in combination. Examples of additives include flame retardants, colorants, anti-aging agents, and antioxidants. The amount of organic polyisocyanate used in the present invention is usually 80 to 120 in terms of isocyanate index.
Preferably it is 85-115, particularly preferably 95-110. The amount of catalyst used is, for example, from about 0.001 to about 5%, based on the weight of the reaction mixture. The amount of blowing agent used can vary depending on the desired density of the polyurethane foam, for example from about 1% to about 20% based on the weight of the reaction mixture. The amount of foam stabilizer used is based on the weight of the reaction mixture, e.g.
~about 5%. The amount of crosslinking agent optionally used can vary depending on the desired hardness of the polyurethane foam, for example from about 1% to about 20%, based on the weight of the reaction mixture. The amount of additive used can vary depending on the desired target values for various applications of the polyurethane foam, such as from about 0.05 to about 30 percent, based on the weight of the reaction mixture. The highly elastic polyurethane foam can be produced by a conventional method, such as a one-shot method, a semi-prepolymer method, or a prepolymer method. Highly elastic polyurethane foam is produced by mixing and reacting raw materials in commonly used production equipment (low-pressure or high-pressure machinery). The high modulus polyurethane foams of the present invention are particularly useful in making flexible mold and slab foams. [Examples] The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples. The composition of the raw materials used in the Examples and Comparative Examples is as follows. (1) Polyol A-1 A polyol with a hydroxyl value of 31, which is obtained by adding PO to glycerin and then adding EO. The amount of terminal addition of EO is 16%. (2) Polyol A-2 A polyol with a hydroxyl value of 28, which is obtained by adding PO to glycerin and then adding EO. The amount of terminal addition of EO is 16%. (3) Polyol A-3 A polyol with a hydroxyl value of 24, which is obtained by adding PO to glycerin and then adding EO. The amount of terminal addition of EO is 14%. (4) Polyol B-1 A polyol with a hydroxyl value of 35, made by adding PO to pentaerythritol and then adding EO.
The amount of terminal addition of EO is 10%. (5) A polyol with a hydroxyl value of 32, which is made by adding PO to pentaerythritol and then adding EO.
The amount of terminal addition of EO is 12%. (6) Polyol B-3 A polyol with a hydroxyl value of 28, which is obtained by adding PO to pentaerythritol and then adding EO.
The amount of terminal addition of EO is 10%. (7) Polyol Polyol A-1/Polyol B-1=50/
50 (wt). (8) Polyol Polyol A-2/Polyol B-2=50/
50 (wt). (9) Polyol Polyol A-3/Polyol B-3=50/
50 (wt). (10) Polyol Polyol A-2/Polyol B-2=30/
70 (wt). (11) Polyol Polyol A-2/Polyol B-2=70/
30 (wt). (12) Polyol C-1 100 parts of a polyol with a hydroxyl value of 33, which was obtained by adding PO to glycerin and then adding EO (terminal addition amount: 14%), and 25 parts of acrylonitrile as an ethylenically unsaturated monomer at 130°C. A polyol with a hydroxyl value of 27 obtained by reacting 1.0 part of azobisisobutyronitrile as an initiator at room temperature. (13) Polyol C-2 100 parts of polyol A-2, 27 parts of acrylonitrile and 15 parts of styrene as ethylenically unsaturated monomers were mixed at a temperature of 120°C with 0.2 parts of bis(4-
A polyol with a hydroxyl value of 20 obtained by reacting t-butylcyclohexyl) peroxydicarbonate as an initiator. (14) Polyol C-3 100 parts of polyol B-2, 27 parts of acrylonitrile and 15 parts of styrene as ethylenically unsaturated monomers were mixed at a temperature of 120°C with 0.2 part of bis(4-
A polyol with a hydroxyl value of 22 obtained by reacting t-butylcyclohexyl) peroxydicarbonate as an initiator. (15) Polyol C-4 100 parts of polyol, 27 parts of acrylonitrile as ethylenically unsaturated monomers, and 15 parts of styrene were heated to 120°C to form 0.2 part of bis(4-t-butylcyclohexyl) peroxydicarbonate. A polyol with a hydroxyl value of 20 obtained by reacting with the following as an initiator. (16) Catalyst-1 Dabco33LV (33% dipropylene glycol solution of triethylene diamine) (17) Catalyst-2 Polycat 41 (amine-based catalyst) [San-Apro
Co., Ltd.] (18) Foam stabilizer-1 L-5309 (polyether siloxane polymer)
[Made by Nihon Unicar Co., Ltd.] (19) Foam stabilizer-2 SRX-274C (polyether siloxane polymer) [Made by Toray Silicone Co., Ltd.] (20) Isocyanate Coronate 1021 [T-80/Cr-MDI =8/2
(wt)] [Made by Nippon Polyurethane Industries Co., Ltd.] Examples 1 to 11 and Comparative Examples 1 to 7 Highly elastic HR-foam was molded by hand foaming under the following conditions using polyols A to C and I. did. [Molding conditions] Liquid temperature: 25℃ Cure temperature: 70℃ Cure time: 5 minutes Mold temperature: 55-60℃ Molding size: 40 x 40 x 10 cm The foaming formula and the physical properties of the obtained foam are as follows:
Tables 1 and 2 show the results. The method for measuring physical properties is as follows. Density (Kg/m ³ ): JIS K 6301 25% ILD (Kg/314cm ² ): JIS K 6382 Tensile strength (Kg/cm ² ): JIS K 6301 Tear strength (Kg/cm): JIS K 6301 Cutting elongation (%): JIS K 6301 Repulsion modulus (%): JIS K 6382 Compression set (%): JIS K 6382

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[Table] [Effects of the Invention] The method for producing a highly elastic polyurethane foam of the present invention can produce a foam having better rebound resilience than conventional methods. Because of the above-mentioned effects, the polyurethane foam obtained by the present invention has excellent cushioning properties and is suitable for applications such as automobile seats and furniture.
It is extremely useful due to its comfortable ride.

Claims (1)

[Scope of Claims] 1. A method for producing a polyurethane foam by reacting an organic polyisocyanate and a polymeric polyol in the presence of a catalyst, a blowing agent, a foam stabilizer, and optionally a crosslinking agent and additives, wherein the polymeric polyol Polyol (A) containing 5 to 25% polyoxyethylene chain based on the weight of (A) at the terminal end having a functional group number of 3 and a hydroxyl value of 22 to 35, and a polyol (A) having a functional group number of 4 and a hydroxyl value of 22 Consisting of a polyol (B) containing 5 to 25% polyoxyethylene chains based on the weight of (B) at the end of ~40, the weight ratio of (A)/(B) is 38/
A method for producing a highly elastic polyurethane foam characterized by using a polyol having a ratio of 62 to 90/10. 2. The method according to claim 1, wherein at least a portion of (A) is modified with an ethylenically unsaturated monomer. 3. The method according to claim 1 or 2, wherein at least a portion of (B) is modified with an ethylenically unsaturated monomer.