JPH04285641A - Production of urethane foam - Google Patents

Abstract

PURPOSE:To produce a micro cell-structured urethane foam having excellent moldability, resilience and abrasion resistance by reaction-foaming a mixture of a specified polyol and a specific urethane prepolymer in the presence of water and an urethane-forming catalyst in a mold. CONSTITUTION:(A) A polyol having two or more active hydrogens and having an active hydrogen equivalent of 1000-2500, >=60% of the OH groups being the primary OH groups, (e.g. an adduct of glycerol to propylene oxide or ethylene oxide) and (B) an urethane prepolymer of B1: an active hydrogen compound having an active hydrogen equivalent of 500-3000, >=50% of the OH groups being the primary OH groups (e.g. the same compound as the component A, satisfied with the conditions) with B2: an organic polyisocyanate (e.g. 2,4- and 2,6-tolylene diisocyanate) are subjected to a foaming reaction in the presence of (C) water in an amount of 0.5-1.5% based on the weight of the component A, (D) an urethane-forming catalyst (e.g. triethylenediamine) and, if necessary, a crosslinking agent and other components to produce the urethane foam having a micro cell structure.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing urethane foam having a microcell structure.

0002

[Prior Art] Conventionally, in the manufacturing method of urethane foam having a microcell structure, CFC-1 was used as a blowing agent.
, CFC-12, HCFC-123, HCFC-141
A method using a fluorocarbon-based foaming agent such as B or a non-fluorocarbon foaming agent such as methylene chloride is known.

0003

[Problem to be Solved by the Invention] However, among these blowing agents, CFC-11 and CFC-12 fall under the regulations of the Montreal Protocol on the use of fluorocarbons ratified in 1987, and they are not subject to this regulation. There is a need to replace it with foaming agents. In addition, HCFC-123 and HCFC-141b, which are fluorocarbon foaming agents that are not subject to regulation,
There was a problem in that the future supply of these materials was unclear, and the urethane foams having a microcell structure manufactured using these materials had insufficient impact resilience. On the other hand, methylene chloride has the problem of solvent regulation and the same problem as above that the resulting foam has insufficient impact resilience. Furthermore, all conventional blowing agents have a problem in that a large amount of blowing agent is used, which increases costs. The present invention uses water, which has no problems in terms of supply and regulation, as a blowing agent in place of conventional blowing agents, and improves the impact resilience, which was a problem in the past, as well as improves moldability (removal time of molded products). The objective of this research is to find a method for producing urethane foam with a microcell structure that has excellent abrasion resistance and good appearance (molded product appearance).

0004

[Means for Solving the Problems] The present inventors have made extensive studies to solve the above problems, and as a result, have arrived at the present invention. That is, the present invention uses the following polyol (1) and the following urethane prepolymer (2) in an amount of 0.5 to 1.5 based on the weight of (1).
% of water, a urethane catalyst (3), and if necessary, a crosslinking agent (4) and other components (5), the foaming reaction is carried out in a mold. This is the manufacturing method. Polyol (1):
It has at least 2 active hydrogens, 60% or more of the OH groups are primary OH groups, and the active hydrogen equivalent is 1000 to 250.
0 polyol. Urethane prepolymer (2): 50% or more of the OH groups are primary OH groups, and the active hydrogen equivalent is 50
It is a urethane compound of 0 to 3000 active hydrogen compound (A) and organic polyisocyanate (B), and has 1 NCO group.
Urethane prepolymer containing 3 to 22% by weight.

In the present invention, examples of the polyol (1) include polyether polyols and polyester polyols in which 60% or more of the OH groups are primary OH groups and have an active hydrogen equivalent of 1,000 to 2,500. Examples of the polyether polyol include compounds having a structure in which alkylene oxide is added to an active hydrogen-containing compound such as a polyhydric alcohol, polyhydric phenol, or amine. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,4
- Dihydric alcohols such as butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol; Trihydric alcohols such as glycerin, trimethylolpropane, trimethylolethane, hexanetriol, triethanolamine; pentaerythritol, methyl glycoside, Tetrahydric alcohols such as diglycerin; Pentahydric alcohols such as adonitol, arabitol, xylitol; Hexahydric alcohols such as sorbitol, mannitol, iditol, talitol, dulcitol; Monosaccharides such as glucose, mannose, fructose, sorbose; sucrose, crehalose , lactose, raffinose, and other polysaccharides; glycol glucosides such as ethylene glycol and propylene glycol; glucosides such as alkane polyols such as glycerin, trimethylolpropane, and hexanetriol; polyglycerols such as triglycerin and tetraglycerin; dipentaerythritol, Polypentaerythritol such as tripentaerythritol; and cycloalkane polyols such as tetrakis(hydroxymethyl)cyclohexanol.

Examples of the polyhydric phenols include monocyclic polyhydric phenols such as pyrogallol, hydroquinone, and phloroglucin; bisphenols such as bisphenol A and bisphenol sulfone; condensates of phenol and formaldehyde (novolac); US Pat. No. 32
Examples include polyphenols described in Japanese Patent No. 65641.

Examples of amines include ammonia; alkanolamines such as mono-, di-, and tri-ethanolamine, isopropanolamine, and aminoethylethanolamine; C1-C20 alkylamines; ethylenediamine, propylenediamine, C2 to C6 alkylene diamines such as hexamethylene diamine; polyalkylene polyamines such as diethylene triamine and triethylene tetramine; aromatic amines such as aniline, phenylene diamine, diaminotoluene, xylylene diamine, methylene dianiline, and diphenyl ether diamine; Examples include alicyclic amines such as isophorone diamine, cyclohexylene diamine, and dicyclohexylmethane diamine; and heterocyclic amines described in Japanese Patent Publication No. 55-21044 such as aminoethylpiperazine.

Two or more of the above active hydrogen-containing compounds can also be used in combination. Among these, preferred are polyhydric alcohols and polyhydric phenols.

Examples of the alkylene oxide to be added to the active hydrogen-containing compound include ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO),
), 1,2-, 1,4-butylene oxide, styrene oxide, and combinations of two or more of these (in this case, block and/or random addition), which are added in polyol (1). 60 of the OH group of
% or more are primary OH groups, and the active hydrogen equivalent is 1000~
Add it to 2500. For example, it is preferable to add the above-mentioned alkylene oxide and add EO to the terminal.

[0010] Examples of the polyester polyol include polyester polyols obtained by reacting the above-mentioned polyhydric alcohols and/or the above-mentioned polyether polyols with any of the following. ■Polycarboxylic acids (adipic acid, sebacic acid, maleic acid, phthalic acid, etc.), anhydrides of these polycarboxylic acids (
ester-forming compounds such as maleic anhydride, phthalic anhydride, etc.) and lower alkyl esters of these polycarboxylic acids (dimethyl terephthalate, etc.). ■Alkyleonoxide (EO, PO, etc.). ■Lactones (ε-caprolactone, etc.). Among the polyols (1), preferred are the aforementioned polyether polyols.

In the active hydrogen compound (A) constituting the urethane prepolymer (2), 50% or more of the OH groups are 1
class OH group and has an active hydrogen equivalent of 500 to 3000,
Examples include polyether polyols and polyester polyols. Examples of polyether polyols include those similar to those exemplified above, and those that satisfy the above-mentioned conditions for OH group and active hydrogen equivalent. The polyester polyols are similar to those exemplified above,
Those satisfying the above-mentioned conditions of OH group and active hydrogen equivalent can be mentioned.

[0012] As the organic polyisocyanate (B),
Those conventionally used in polyurethane production can be used. Such organic polyisocyanates (B) include aromatic polyisocyanates having 6 to 20 carbon atoms (excluding carbon in the NCO group) [for example, 2,4- and/or 2,6-tolylene diisocyanate (TDI)].
, crude TDI, 2,4'- and/or 4,4'
- diphenylmethane diisocyanate (MDI), crude MDI {a phosgenate of crude diaminophenylmethane (a condensation product of formaldehyde and an aromatic amine or a mixture thereof), diaminodiphenylmethane and a small amount (e.g. 5-20% by weight) of trifunctional or higher functional phosgenates in mixtures with polyamines, polyallyl polyisocyanates, etc.}; 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); carbon number 8
~15 aromatic aliphatic polyisocyanates (for example, xylylene diisocyanate, etc.); and modified products of these polyisocyanates (urethane group, carbodiimide group, allophanate group, urea group, biuret group, uretdione group, uretonimine group, isocyanurate group) ,
oxazolidone group-containing modified products, etc.); and patent application filed in 1983.
Examples include polyisocyanates other than those described in JP-A-199160; and mixtures of two or more thereof. Among these, polyisocyanates such as 2,4- and 2,6-TDI, and mixtures thereof, 4,4'
- and 2,4'-MDI, and mixtures thereof, crude MDI, and modified products of these polyisocyanates (
urethane group, carbodiimide group, allophanate group, urea group, biuret group, or isocyanurate group-containing modified product).

(1) 60% or more of the OH groups are primary OH
group, and has an active hydrogen equivalent of 1000 to 2500. If the primary OH group content is less than 60%, the resin strength of the molded article will decrease, the wear resistance will decrease, and the moldability will also deteriorate. When the active hydrogen equivalent is less than 1000, moldability deteriorates and the impact resilience of the molded article deteriorates. Furthermore, if the active hydrogen equivalent exceeds 2,500, the viscosity of the polyol increases and a uniform molded product cannot be obtained. In (A), 50% or more of the OH groups are primary OH groups, and the active hydrogen equivalent is 500 to 3,000. 5 primary OH groups
If it is less than 0%, moldability deteriorates. Furthermore, if the active hydrogen equivalent is outside this range, the physical properties of the molded article, particularly the impact resilience, abrasion resistance, and elongation rate will deteriorate, which is not preferable for the production method of the present invention. (2) is a urethane prepolymer containing 13 to 22% by weight of NCO groups. If the NCO group content is less than 13%, deterioration in moldability is observed. If the NCO group exceeds 22%, the physical properties of the molded article will deteriorate, which is not preferable for the production method of the present invention.

In the present invention, the ratio of (1) and (2) used in the production of polyurethane foam is such that the isocyanate index is usually 70 to 120, preferably 80 to 10.
Adjust so that it becomes 5.

Examples of the urethanization catalyst (3) include tertiary amines such as triethylenediamine, tetramethylhexamethylenediamine, and N-ethylmorpholine; and organotin compounds such as stannous octylate and dibutyltin dilaurate. It will be done. The amount of urethanization catalyst (3) is usually 0.001 to 7% based on the weight of (1).
It is.

Examples of the crosslinking agent (4) used in combination if necessary include low-molecular polyols such as ethylene glycol and diethylene glycol; and polyamines such as triethanolamine and diethanolamine.

Additives that can be used as other components (5) in the present invention include flame retardants, colorants, anti-aging agents, antioxidants, foam stabilizers, bactericidal agents, carbon black, and other fillers. Known additives may be mentioned.

Injection of polyurethane foam raw materials is normally carried out by using a low-pressure or high-pressure injection device to mix and react the raw materials and discharge them into a mold.

[Examples] The present invention will be specifically explained below using Examples, but the present invention is not limited thereto.

The raw materials for polyurethane foam in Examples and Comparative Examples are as follows. (1) Polyol A: PO and EO added to glycerin, primary OH is 82% of total OH, active hydrogen equivalent 2
000 polyether polyol. (2) Polyol B: PO and EO added to glycerin, primary OH is 75% of total OH, active hydrogen equivalent 2
300 polyether polyol. (3) Polyol C: PO added to glycerin,
Polyether polyol with active hydrogen equivalent of 2000 and 0% primary OH in total OH. (4) Polyol D: A polyether polyol in which PO and EO are added to propylene glycol, and the primary OH accounts for 80% of the total OH and has an active hydrogen equivalent of 2000. (5) Polyol E: A polyether polyol in which PO and EO are added to propylene glycol, the primary OH is 85% of the total OH, and the active hydrogen equivalent is 1000. (6) EG: ethylene glycol. (7) Catalyst: triethylenediamine. (8) Isocyanate 1: A polyether polyol obtained by adding PO and EO to glycerin, in which primary OH accounts for 76% of the total OH and has an active hydrogen equivalent of 1300, and MDI
NCO content 15.5% modified by urethanization with
urethane prepolymer. (9) Isocyanate 2: PO is added to glycerin, primary OH accounts for 0% of total OH, and active hydrogen equivalent is 1
A urethane prepolymer with an NCO content of 15.5% modified by urethanization of 300 polyether polyol and MDI. (10) Isocyanate 3: Millionate MTL Carbodiimide modified liquid MDI (NCO content 28.8%)
[Made by Nippon Polyurethane Co., Ltd.].

Examples 1 to 3 Components A and B shown in Table 1 were mixed using a high-pressure foaming machine (KURAUSS MAFFEI machine), and a 1000×4
It was injection molded into a closed mold of 0.00 x 5 mm. Table 1 shows the results of measuring the physical properties of each foam under each molding condition.
Shown below.

[0021]

[Table 1]

Comparative Examples 1 to 4 Components A and B shown in Table 2 were mixed using a high-pressure foaming machine (KURAUSS MAFFEI machine), and a 1000×4
It was injection molded into a closed mold of 0.00 x 5 mm. Table 2 shows the results of measuring the physical properties of each foam under each molding condition.
Shown below.

[0023]

[Table 2]

[0024]

Effects of the Invention Since the method of the present invention uses water as a blowing agent, there is no need to worry about the regulation of blowing agents or problems in supply as in the past. Moreover, the urethane foam having a microcell structure obtained by the method of the present invention has excellent appearance, impact resilience, and abrasion resistance of molded products. Further, in the case of conventional blowing agents, 10 to 20 parts are usually required per 100 parts by weight of the polyol component, whereas in the case of water of the present invention, 0.5 to 1.5 parts may be used. Therefore, it is also advantageous in terms of cost. Because of the above-mentioned effects, the manufacturing method of the present invention can be applied to a wide range of fields, such as the manufacturing of automobile handles that require wear resistance.

Claims (1)

[Claims] Claim 1: The following polyol (1) and the following urethane prepolymer (2) are mixed in an amount of 0.5 to 1% by weight based on the weight of (1).
．． A urethane having a microcellular structure characterized by carrying out a foaming reaction in a mold in the presence of 5% water, a urethanization catalyst (3), and, if necessary, a crosslinking agent (4) and other components (5). Form manufacturing method. Polyol (1): has at least 2 active hydrogens, 60% or more of the OH groups are primary OH groups, and the active hydrogen equivalent is 1000 to 2500
polyol. Urethane prepolymer (2): 50% or more of the OH groups are primary OH groups, and the active hydrogen equivalent is 500
It is a urethane compound of ~3000 active hydrogen compound (A) and organic polyisocyanate (B), and has an NCO group of 13
Urethane prepolymer containing ~22% by weight.