JPH06172477A - Production of polyurethane foam - Google Patents

Abstract

PURPOSE:To obtain the subject foam with few foam defects, excellent in uniformity, reproducibility, and biodegradability, useful as a thermal insulating material, etc., by neutralizing under specified conditions a reaction liquor containing a specific liquefied lignocellulose material followed by reaction with a polyisocyanate in the presence of a foaming agent. CONSTITUTION:A reaction liquor containing a liquefied lignocellulose material prepared by reaction between a lignocellulose material and a polyhydric alcohol such as ethylene glycol in the presence of an acid catalyst is neutralized with a primary amine compound and/or secondary amine compound such as an imidazole compound (may contain an alkali (alkaline earth) metal hydroxide) followed by reaction with a polyisocyanate such as phenylene diisocyanate in the presence of a foaming agent such as water, thus affording the objective foam.

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 a polyurethane foam having properties such as low combustion heat value and biodegradability by liquefying a lignocellulosic material such as wood in the presence of a polyhydric alcohol and an acid catalyst. It is a thing.

[0002]

2. Description of the Related Art There is a method of utilizing a lignocellulosic material such as an unused material, a waste material, and a scrap material as a raw material of a polyurethane foam. When used as a raw material for polyurethane foam, the lignocellulosic material must be in liquid form. A liquefaction method is already known in Japanese Patent Laid-Open No. 4-106128, etc., but an acid catalyst such as sulfuric acid is used as a catalyst during liquefaction. If these acids remain, problems such as reaction delay occur during the production of the polyurethane foam, so it is necessary to neutralize these acids with a neutralizing agent. Conventionally, as the neutralizing agent, hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide and barium hydroxide have been used.

[0003]

Among the above-mentioned neutralizing agents such as hydroxides of alkali metals or alkaline earth metals, since these neutralizing agents exhibit a strong catalytic activity in the reaction for forming polyurethane, the neutralizing agents are The reactivity and moldability of the foam greatly differed depending on the amount added, and there was a problem in the uniformity and reproducibility of the resulting foam. An object of the present invention is to provide a polyurethane foam which has industrially useful uniformity, reproducibility, and few foam defects.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive studies made by the present inventors to solve such conventional problems, the first
It has been found that a polyurethane foam having no foam defect can be easily obtained by using a secondary amine compound and / or a secondary amine compound as a neutralizing agent for all or a part of them, and has completed the present invention. That is, the present invention is
The reaction liquid containing a liquefied lignocellulosic material obtained by reacting a lignocellulosic material with a polyhydric alcohol in the presence of an acid catalyst may also contain an alkali metal hydroxide and / or an alkaline earth metal hydroxide. Neutralize with a good primary amine compound and / or secondary amine compound,
Then, the method is a method for producing a polyurethane foam having a uniform cell structure, which comprises reacting with a polyisocyanate in the presence of a foaming agent.

As the liquefied lignocellulosic material of the present invention, all known ones obtained by reacting a lignocellulosic material in the presence of an acid catalyst and a polyhydric alcohol can be used (for example, JP-A-4-106128). reference). Examples of the lignocellulosic material include wood powder, wood fiber, wood chips and veneer waste, straw and chaff, ground pulp, thermomechanical pulp, waste paper and other papers, or pulps. Specific examples of wood include citrus birch, sitka spruce, cedar, red pine, poplar, waran, and the like. The lignocellulosic material may be subjected to a pretreatment with, for example, halogen (see JP-A-63-17961). Polyhydric alcohols are dihydric or higher alcohols, and examples thereof include aliphatic polyhydric alcohols, polyether polyols, polyester polyols, and the like, with polyethylene glycol, glycerin, and ethylene glycol being particularly preferable. Polyhydric alcohols may be used alone,
Further, two or more of them may be appropriately mixed and used, and it is preferable to use a polyhydric alcohol having a relatively large molecular weight and a polyhydric alcohol having a relatively small molecular weight together. Further, for the purpose of lowering the viscosity of the solution or facilitating the liquefaction / dissolution, one or more kinds of water or an organic solvent such as monohydric alcohol, acetone, ethyl acetate or the like from the beginning or during the liquefaction / dissolution. It is also possible to add and coexist. These organic solvents are usually added in an amount of preferably 1 to 10 parts by weight, based on 100 parts by weight of the polyhydric alcohol. The liquefaction reaction is particularly carried out at normal pressure in the presence of an acid catalyst.
The acid catalyst may be a mineral acid, an organic acid, or a Lewis acid, such as sulfuric acid, hydrochloric acid, toluenesulfonic acid, phenolsulfonic acid, aluminum chloride, zinc chloride or boron trifluoride. The reaction temperature is 100 to 200 ° C,
It is preferably 150 to 160 ° C. The reaction liquid containing the liquefied lignocellulosic material is preferably used after filtering after the liquefaction reaction.

The liquefied lignocellulosic material of the present invention comprises:
An active hydrogen compound can be added if necessary.
As the active hydrogen compound, polyether polyol, polyester polyol, polycarbonate polyol, etc. having a molecular weight of 200 to 10,000 used as a reaction partner of polyisocyanate are used. Examples of the polyether polyol include a polymerization product of tetrahydrofuran, propylene oxide and / or ethylene oxide, and a copolymer thereof or a graft polymer with a vinyl monomer. Examples of the polyester polyol include those obtained from polyhydric alcohols and polycarboxylic acids by a known method. Examples of the polyhydric alcohols include ethylene glycol, diethylene glycol, butylene glycol, hexamethylene glycol, neopentyl glycol, 3-
Examples include methylpentanediol, cyclohexanedimethanol, glycerin, and trimethylolpropane.
Examples of polyvalent carboxylic acids include succinic acid, adipic acid, sebacic acid, dimer acid, phthalic acid, phthalic acid alkyl esters, trimellitic acid, pyromellitic acid, maleic acid, fumaric acid, and itaconic acid. Also,
Also included are those obtained by ring-opening polymerization of cyclic esters such as butyrolactone, valerolactone, caprolactone. As a polycarbonate polyol, 1,
An aliphatic diol or an alicyclic diol such as 6-hexanediol or 1,4-cyclohexanedimethanol,
Mention may be made of polycarbonate diols obtained by transesterification with cyclic carbonates such as dialkyl carbonates or diaryl carbonates or ethylene carbonates. Also, polyols such as those already containing urethane groups or urea groups, castor oil,
Natural polyols such as tar oil and carbohydrates can also be used. The amount of these active hydrogen compounds added is 1 with respect to 100 parts by weight of the liquefied lignocellulosic material.
-100 parts by weight is preferred.

As the primary amine compound of the present invention, any compound having a primary amino group in the molecule can be used. For example, benzylamine, hexylamine, octylamine, 2,4-diamino-6- [2'-
Methylimidazolyl (1 ′)] ethyl-S-triazine, ethylenediamine, diethylenetriamine, monoethanolamine and the like can be mentioned. As the secondary amine compound, any compound having a secondary amino group in the molecule can be used. Examples thereof include N-methylhexylamine, N-ethyloctylamine, diethylenetriamine, N-methylbenzylamine, N-methylcyclohexylamine, morpholine and diethanolamine. In addition, for example, imidazole, 2-methylimidazole, 4-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 1-undecylimidazole, 2-heptadecylimidazole, 2-
Ethyl-4-methylimidazole, 2-phenyl-4-
Methylimidazole, 2,4-diamino-6- [2'-
Methylimidazolyl (1 ′)] ethyl-S-toluazine, 2,4-diamino-6- [2′-undecylimidazolyl (1 ′)] ethyl-S-toluazine, 2,4-diamino-6- [2 ′ -Ethyl-4-methylimidazolyl (1 ')] ethyl-S-toluazine, 2-phenyl-4
-Methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-hydroxymethylimidazole, 2-
Preferable examples include imidazole compounds having an imidazole ring, such as alkyl-4-formylimidazole, 2-alkyl-5-formylimidazole, addition products of these alkyl groups, and derivatives. As the neutralizing agent, the above-mentioned primary amine compound and secondary amine compound can be used alone or in combination, and an imidazole compound is particularly preferable. The method for mixing the reaction liquid containing the liquefied lignocellulosic material of the present invention and the primary amine compound and / or the secondary amine compound is such that the primary amine compound and / or the secondary amine compound is produced immediately after the production of the liquefied lignocellulosic material. An amine compound may be added and mixed, or a method in which an active hydrogen compound is added after the production of the liquefied lignocellulosic material and then mixed may be used. The addition amount of the primary amine compound and / or the secondary amine compound is an amount that neutralizes a part or all of the acid catalyst used during the production of the liquefied lignocellulosic material. Further, it is possible to neutralize by partially using a hydroxide of an alkali metal such as sodium hydroxide, potassium hydroxide or calcium carbonate, or an alkaline earth metal.

The polyisocyanate used in the present invention includes the following materials. Phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tetramethyl xylene diisocyanate, naphthylene diisocyanate, diphenylmethane diisocyanate, etc., and aromatic diisocyanates composed of these isomers, 1,6-hexamethylene diisocyanate, 1,12-
Aliphatic diisocyanates such as dodecane diisocyanate, and cycloaliphatic diisocyanates such as cyclohexane diisocyanate, dicyclohexylmethane diisocyanate and isophorone diisocyanate can be mentioned. Further, an isocyanate group-terminated compound obtained by reacting these compounds with an active hydrogen group-containing compound or a polyol having a molecular weight of 200 or more, or an isocyanate modified product obtained by a reaction of these compounds (for example, a carbodiimidization reaction) can also be mentioned. . Further, polyisocyanates partially or wholly stabilized with a blocking agent having one active hydrogen in the molecule, such as methanol, n-butanol, benzyl alcohol, ethyl acetoacetate, ε-caprolactam, methyl ethyl ketone oxime, phenol and cresol. And so on.

As the foaming agent and the foam stabilizer of the present invention, all the foaming agents and foam stabilizers used in ordinary urethane foaming can be used. Examples of the foaming agent include water,
Freon 11, Freon 12, Freon 22, Freon 141
b, methylene chloride. Examples of the foam stabilizer include SH of Toray Dow Corning Silicone Co., Ltd.
-193, F-341 manufactured by Shin-Etsu Chemical Co., Ltd., L-5420 manufactured by Nippon Unicar Co., Ltd., and the like. The foam stabilizer is 0.1 to 100 parts by weight of the liquefied lignocellulosic material.
It is preferred to use 10 parts by weight. The foaming agent is 0.1 to 100 with respect to 100 parts by weight of the liquefied lignocellulosic material.
It is preferred to use parts by weight.

The method for producing a polyurethane foam of the present invention comprises a mixture of a reaction liquid containing a liquefied lignocellulosic material and a primary amine compound and / or a secondary amine compound, to which a foaming agent is added (hereinafter, polyol premix). That is) is basically a method of mixing with a polyisocyanate. The composition of the polyol premix and the polyisocyanate is such that the active hydrogen groups of the polyol premix are 30 to 30 mol per 100 mol of the NCO group of the polyisocyanate.
200 mol is preferred. More preferably, NCO group 1
The amount of active hydrogen group is 70 to 150 mol per 100 mol.
A polyurethane foaming catalyst can be added to adjust the foaming rate. As such a catalyst, all the catalysts normally used for polyurethane foaming can be used. For example, TOYOCAT-NP of Tosoh Corporation,
Kao Co., Ltd. Kaolizer No. 1, Kaolizer N
o. 14 and the like. In order to adjust the viscosity of the polyol premix, a plasticizer or the like can be added. For example, dioctyl phthalate, tricresyl phosphate, propylene carbonate, ethylene carbonate and the like are used. As a device for obtaining the polyurethane foam of the present invention, any device used for ordinary polyurethane foaming can be used. The conditions for foaming, such as the raw material temperature, the mold temperature, and the stirring speed, can be the same as those used in ordinary polyurethane foaming. In the polyurethane foam obtained by the present invention, other substances as necessary during foaming, such as antioxidants, ultraviolet absorbers, heat resistance improvers, flame retardants, colorants, inorganic and organic fillers, plasticizers, Lubricants, antistatic agents, reinforcing materials and the like can be added.

[0011]

Industrial Applicability According to the present invention, when producing a polyurethane foam, it is possible to expand the range of foaming conditions such as pH, and further improve the uniformity of the cell structure of the foam and the expansion ratio. Since it is possible to obtain a polyurethane foam which is excellent in its reproducibility of production and has few foam defects, as a result, it brings about a great effect on the utilization of the lignocellulosic material which is a part of the effective utilization of wood resources. Among the polyurethane foams, those exhibiting biodegradability are also recognized, but since the present invention contains a biodegradable substance called a lignocellulosic substance as one of its constituent main components, its properties are promoted. become.
The polyurethane foam obtained in the present invention has various heat insulating materials,
It is effectively used for synthetic wood, cushioning materials, cushioning materials, and various sealing materials.

[0012]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In Examples and Comparative Examples,
All "%" mean "% by weight". Example 1 40 g of dried cedar flour was combined with 120 g of polyether polyol G-300 (average molecular weight 300, manufactured by Asahi Denka Co., Ltd.) in which 3.6 g of 98% sulfuric acid was mixed in advance, and 500 ml equipped with a reflux condenser. It was put in a glass flask and stirred and reacted in an oil bath at 150 ° C. for 1 hour to obtain a liquefied lignocellulosic material. When the hydroxyl value of the obtained liquefied lignocellulosic material was measured, it was 310 mgK.
It was OH / g. Then, 20 g of the solution cooled to room temperature was placed in a 200 ml beaker, and 0.7 g of imidazole as a primary amine compound and / or a secondary amine compound was added and stirred sufficiently. SH-1 as foam stabilizer
93 (manufactured by Toray Dow Corning Silicone Co., Ltd.) 0.2
g and 1 g of water as a foaming agent were added and mixed and stirred, and then, as a polyisocyanate, Millionate MR-10
32 (NCO content 31.0%, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to obtain 7,000 rpm. p. m. In 10
It was stirred for 2 seconds and poured into a 1000 ml cup to obtain a polyurethane foam. The obtained polyurethane foam had a homogeneous cell and a specific gravity of 0.038 g / cc, and no void was generated.

Example 2 21 g of a foaming raw material mixed and stirred in the same manner as in Example 1 was filled in a 100 × 100 × 50 mm aluminum box mold. The obtained polyurethane foam had a homogeneous cell and a specific gravity of 0.042 g / cc, and no void was generated. No deformation was observed in the foam that was left at -20 ° C for 2 days. Example 3 To 20 g of the same liquefied lignocellulosic material as in Example 1 was added 0.8 g of morpholine as a primary and / or secondary amine compound, and the mixture was sufficiently stirred and SH-as a foam stabilizer.
193 (manufactured by Toray Dow Corning Silicone Co., Ltd.)
2g, TOYOCAT MR as a catalyst (Tosoh Corp.)
0.2 g) and 1.3 g of water as a foaming agent are added and mixed and stirred, and then Millionate MR-200 (NCO
31.0% content, made by Nippon Polyurethane Industry Co., Ltd. 3
7 g and 7,000 r.p. p. m. Stir for 10 seconds, 1
It was poured into a 000 ml cup to obtain a polyurethane foam.
This foam is a homogeneous cell with a specific gravity of 0.032 g / cc
There was no occurrence of voids. Example 4 Foaming raw material 21.5 mixed and stirred in the same manner as in Example 3
g was filled in the same mold as in Example 2. The resulting polyurethane foam is a homogeneous cell with a specific gravity of 0.037 g.
/ Cc, and similarly, no void was generated. Example 5 First to 20 g of the same liquefied lignocellulosic material as in Example 1
1.4g of imidazole as a secondary and / or secondary amine compound is added, and the same million ion MR as in Example 1 is added.
A polyurethane foam was obtained in the same manner as in Example 1, except that 42 g of -100 was used. This foam had a homogeneous cell and a specific gravity of 0.040 g / cc, and no void was generated. Example 6 48 to 20 g of the same liquefied lignocellulosic material as in Example 1
% Sodium hydroxide solution 0.4 g, and 2-methylimidazole 0.4 g as a primary and / or secondary amine compound are added and sufficiently stirred to obtain a foam stabilizer F-341.
(Shin-Etsu Chemical Co., Ltd.) 0.2 g, water as a foaming agent 0.8
g, and after mixing and stirring, the isocyanate M
R-300 (NCO content 30.8%, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added in an amount of 26 g to give 7,000 rpm. p. m. After stirring for 10 seconds, the mixture was poured into a 1000 ml cup to obtain a polyurethane foam. This foam had a homogeneous cell and a specific gravity of 0.042 g / cc, and no void was generated. Example 7 16 g of the same liquefied lignocellulosic material as in Example 1 was added to polyether polyol SC-1000 (Asahi Denka Kogyo KK).
4 g), imidazole 0.6 g as a primary and / or secondary amine compound, and sufficiently stirred, SH-193 (manufactured by Toray Dow Corning Silicone Co., Ltd.) 0.2 g as a foam stabilizer, and a foaming agent After adding 1 g of water and mixing and stirring respectively, Millionate MR-100 (N
CO content 31.0%, manufactured by Nippon Polyurethane Industry Co., Ltd.
33 g of 7000 r. p. m. After stirring for 10 seconds, the mixture was poured into a 1000 ml cup to obtain a polyurethane foam. This foam is a homogeneous cell with a specific gravity of 0.045g.
/ Cc, and no void was generated.

Comparative Example 1 48 g of 20 g of the same liquefied lignocellulosic material as in Example 1
% Sodium hydroxide solution (0.9 g) and sufficiently stirred,
SH-193 (manufactured by Toray Dow Corning Silicone Co., Ltd.) as a foam stabilizer and 0.6 g of water as a foaming agent were added and mixed and stirred, and then Millionate MR-100.
(NCO content 31.0%, Nippon Polyurethane Industry Co., Ltd.
36 g), and 7,000 r.p. p. m. After stirring for 10 seconds, the mixture was poured into a 1000 ml cup to obtain a polyurethane foam. This foam has a non-homogeneous cell with a specific gravity of 0.04
It was 9 g / cc, and generation of voids was observed. Comparative Example 2 A polyurethane foam obtained in the same manner as in Comparative Example 1 except that the amount of 48% sodium hydroxide solution used was 0.4 g and the amount of water used was changed to 1 g in the method of Comparative Example 1, It caused a fairly severe contraction. Comparative Example 3 In the method of Comparative Example 1, the product obtained by the same method as in Comparative Example 1 except that the amount of the 48% sodium hydroxide solution used was changed to 1.8 g and water was not used, was a normal foam. It didn't happen.

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Claims (4)

[Claims] 1. A reaction liquid containing a liquefied lignocellulosic substance obtained by reacting a lignocellulosic substance and a polyhydric alcohol in the presence of an acid catalyst is treated with an alkali metal hydroxide and / or an alkaline earth metal hydroxide. A polyurethane foam having a uniform cell structure, characterized in that it is neutralized with a primary amine compound and / or a secondary amine compound which may contain Body manufacturing method. 2. The production method according to claim 1, wherein the primary amine compound and / or the secondary amine compound is an imidazole compound. 3. A reaction solution containing a liquefied lignocellulosic material obtained by reacting a lignocellulosic material with a polyhydric alcohol in the presence of an acid catalyst is used to prepare an active hydrogen compound, an alkali metal hydroxide and / or an alkaline earth metal. Homogeneous cell characterized by being neutralized with a primary amine compound and / or a secondary amine compound which may contain a metal hydroxide, and then reacted with a polyisocyanate in the presence of a blowing agent. A method for producing a polyurethane foam having a structure. 4. A reaction solution containing a liquefied lignocellulosic material obtained by reacting a lignocellulosic material and a polyhydric alcohol in the presence of an acid catalyst is treated with an alkali metal hydroxide and / or an alkaline earth metal hydroxide. Homogeneous, characterized in that it is neutralized with a primary amine compound and / or a secondary amine compound, which may contain a further active hydrogen compound, and then reacted with a polyisocyanate in the presence of a blowing agent. For producing a polyurethane foam having a uniform cell structure.