JPH05306325A - Formed polyurethane foam - Google Patents

Abstract

PURPOSE:To obtain a formed material having excellent abrasion resistance even in the case of exclusively using water as the foaming agent to cope with the fluorocarbon restriction and useful as automobile parts such as steering wheel by using a specific polyisocyanate. CONSTITUTION:This formed material is produced by reacting (A) a polyisocyanate consisting of a prepolymer containing terminal NCO group and obtained by reacting an organic polyisocyanate containing polymethylene polyphenyl polyisocyanate as an essential component with a poly(oxytetramethylene) glycol with (B) a polyol in the presence of (C) a foaming agent (preferably water). The component B is preferably a polymer polyol obtained by reacting a polyether polyol with ethylenic unsaturated monomers containing acrylonitrile as an essential component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane foam having excellent wear resistance, which is suitable for use in automobile members such as handles, headrests and armrests, furniture and the like.
Regarding molded products.

[0002]

2. Description of the Related Art The production of integral skin foams having a fine skin is well known, and the products are widely applied to automobile parts (especially steering wheel, headrest, armrest, etc.) and furniture. ing. In such an integral skin foam, chlorofluorocarbon (CFC) acts as a foaming agent to form a skin layer due to heat generated by the reaction between polyisocyanates and polyols. The formation of this skin layer contributes to the abrasion resistance required for products used for the above applications.

[0003]

In recent years, CFCs have been pointed out as a cause of ozone layer depletion on the earth, and their use will be restricted or abolished in the future. In that case, there is a solution in which water is used as an alternative to CFCs. However, in the conventional technique, a foam foamed with water alone has a skin layer higher than that foamed with CFCs. There is a problem that it is difficult to form and wear resistance is poor. SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyurethane foam molded article having excellent wear resistance that solves the above problems.

[0004]

As a result of intensive studies in view of the above-mentioned circumstances, the present inventor has found that the above object can be achieved by using a specific polyisocyanate, and has completed the present invention. I arrived. That is, the gist of the present invention is a polyurethane foam molded article obtained by reacting a polyisocyanate with a polyol in the presence of a foaming agent, wherein polymethylene polyphenyl is used as the polyisocyanate. A polyurethane foam characterized by using a prepolymer containing a terminal isocyanate group obtained by reacting an organic polyisocyanate containing polyisocyanate as an essential component with poly (oxytetramethylene) glycol It is found in molded products.

The present invention will be described in detail below. In the present invention, as polyisocyanates, an organic polyisocyanate containing polymethylene polyphenyl polyisocyanate (polymeric MDI) as an essential component is reacted with poly (oxytetramethylene) glycol (PTMG). It is necessary to use the resulting terminal isocyanate group-containing prepolymer (PTMG-based prepolymer).

As the organic polyisocyanate, polymeric MDI is used as an essential component, and as other polyisocyanates used in combination, aliphatic, cycloaliphatic,
Known materials in the polyurethane or polyurea industry such as araliphatic or aromatic polyisocyanate are used. Suitable organic polyisocyanates include 1,6
-Hexamethylene diisocyanate, cyclohexane-
1,4-diisocyanate, 1,4-xylylene diisocyanate, 2,4-toluene diisocyanate, 2,
Introduction of 6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, or urethane, urea, biuret, carbodiimide, uretonimine or isocyanurate residue Modified polyisocyanate modified by
And the like, and these may be used alone or as a mixture. Among these organic polyisocyanates, aromatic polyisocyanates are particularly preferable, and representative examples thereof include MDI isomers, that is, 4,4'-diphenylmethane diisocyanate and 2,4-diphenylmethane diamine. Isocyanates and mixtures thereof, modified products thereof and the like can be mentioned.

Poly (oxytetramethylene) glycol (PTMG) is a linear polyether glycol having primary hydroxyl groups at both ends and has a weight average molecular weight of 300-.
3,000 is used. The prepolymer of the present invention
In the production of, the average molecular weight is preferably in the range of 500-2,400.

The PTMG-based prepolymer of the present invention heats excess organic polyisocyanate and PTMG under heating (40
It is obtained by reacting at -100 ° C. Usually, the isocyanate (NCO) content in the prepolymer is 14-28% by weight, and the PTMG content is 10-50% by weight, preferably 20-45% by weight. The content of the polymeric MDI in the prepolymer is 1-40% by weight, preferably 2-30% by weight, more preferably 5-20%.
Weight%

Examples of the polyols of the present invention include:
Alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) is used as a low molecular weight polyol (ethylene glycol, propylene glycol).
, Glycerin, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol, sucrose, etc.) and polyamines (ethylenediamine,
Polyethylene polyol added to diethylenetriamine, tolylenediamine, xylylenediamine, piperazine, NN dimethylaminoalkylamine, etc., polyetherpolyol and ethylenically unsaturated monomer (acrylonitrile, styrene, butadiene, Polymer-polyol reacted with methyl methacrylate, acrylic acid amide, vinyl acetate, etc., or polycarboxylic acid (succinic acid, maleic acid, sebacic acid, adipic acid, fumaric acid,
Phthalic acid, dimer acid, etc.) and the polyester obtained by the reaction of the above low molecular weight polyol.

In the present invention, among these polyols, from the viewpoint of improving the wear resistance which is the object of the present invention, a new finding was found that polymer polyol is suitable. . As a suitable polymer-polyol, one using acrylonitrile as an ethylenically unsaturated monomer is preferable, and acrylonitrile alone or a copolymer of acrylonitrile and styrene and the like can be mentioned. .. However, although the use of polymer-polyol is advantageous for improving the wear resistance, the amount of the polymer-polyol used is determined in consideration of moldability and the like because of its high viscosity. In the present invention, it is 25-80% by weight, preferably 30-70% by weight, and more preferably 35-60% by weight in the polyols.

As the foaming agent of the present invention, water or CF is used.
A single type or a mixture of type C is used, but water is preferably used. The amount of water used is 0.05-5 parts by weight, preferably 0.1-3, relative to 100 parts by weight of polyols.
By weight, more preferably 0.3-2 parts by weight.
As the foaming agent, a low boiling point solvent such as pentane, methylene chloride, dichloromethane, 4,4'-diaminodiphenylmethane can be used together.

In the present invention, a crosslinking agent is appropriately used. Suitable crosslinking agents include triethanolamine,
Amine-based low molecular weight polyols such as diethanolamine,
Examples thereof include low molecular weight polyols such as ethylene glycol, diethylene glycol, butanediol, trimethylolpropane, and glycerin. These crosslinkers are
They can be used alone or as a mixture. The amount of the cross-linking agent used varies depending on the kind of the cross-linking agent, but is usually
The amount is 2 to 20 parts by weight, preferably 3 to 10 parts by weight, based on 100 parts by weight of the wax.

In the present invention, a urethanization catalyst is appropriately used. Suitable catalysts include tertiary amines or organotin compounds, and examples of organotin compounds include:
Examples thereof include dibutyltin dilaurate, dibutyltin diacetate, dihexyltin diacetate, di-2-ethylhexyltin oxide, stannous octoate, and stannous oleate. Examples of tertiary amines include trimethylamine, trialkylamines such as triethylamine, N
A multi-membered amine such as an alkyl morpholine, 2,
Ethers such as 2'-bis (dimethylamino) diethyl ether, 1,4-dimethylpiperazine, triethylenediamine, N, N, N ', N'-tetramethyl-
Examples include aliphatic polyamines such as 1,3-butanediamine and N-methyldiethanolamine. These catalysts may be used alone or as a mixture. The amount of the catalyst used varies depending on the type, but is usually 10 parts by weight or less per 100 parts by weight of the polyols.

In the present invention, in addition to the above materials, auxiliary agents such as emulsifiers, stabilizers, surfactants, fillers, colorants, and oxidation stabilizers can be used if necessary. Further, the polyurethane foam molded article of the present invention can be produced by a conventionally known method, for example, a molding method such as an open mold method or a closed mold method.

[0015]

EXAMPLES The present invention will be specifically described below based on Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist. The reaction components used in the following examples are as follows, and "parts" and "%" are based on weight unless otherwise specified.

(1) Polyisocyanate As an organic polyisocyanate component, diphenylmethane diisocyanate (I-125: NCO content 33.6).
%), Carbodiimide-modified MDI (I-143L: NC
O content 29.4%) and polymeric MDI (PAP
I-135: NCO content 31%), and
Average molecular weight of 700, 1000 and 150
0 PTMGs (PTMG700 and PTMG10 respectively)
00, referred to as PTMG1500), propylene oxide (PO) was added thereto using glycerin as an initiator, and the end was capped with ethylene oxide (EO), and the average equivalent number 1600 of polyetherpolyol (EO content: 14%, hereinafter referred to as polyol P1) was selected. A prepolymer containing a terminal NCO group was produced by a conventional method using the above-mentioned components of the organic polyisocyanate and the polyol. The composition of the obtained prepolymer is shown in Table 1.
And shown in Table 2.

(2) Polyols Polyol P2: Polyether polyol having a functionality of 3, an average equivalent number of 1600, a terminal EO content of 17% and a PO content of 83%. This polyetherpolyol was obtained by using glycerin as an initiator, adding PO in the presence of a potassium hydroxide catalyst, and then capping the ends with EO. Polyol CPP1: A polymer polyol having a functionality of 3 and a hydroxyl value of 28. This polymer-polyol was obtained by polymerizing acrylonitrile with the above-mentioned polyol P2 (solid content: 20%). Polyol CPP2: A polymer polyol having a functionality of 3 and a hydroxyl value of 28. This polymer-polyol is obtained by adding acrylonitrile / styrene (70/3) to the above-mentioned polyol P2.
0) was copolymerized (solid content: 20%).

(3) Additive Catalyst: Amine catalyst 1: Triethylenediamine (33% solution of dipropylene glycol) (Dabco 33L)
V: Air Product Co., Ltd.) Amine-based catalyst 2: Bis (dimethylaminoethyl) ether (NIAXA-1: Union Carbide Co.) Crosslinking agent: Monoethylene glycol (MEG) Blowing agent: Water, trichloro Fluoromethane (CFC-1
1)

Examples 1-14 and Comparative Examples 1-2 Polyurethane foam molded articles (car handles) were prepared in the following manner according to the formulations shown in Tables 3, 4 and 5.
Was manufactured. All other ingredients except the polyisocyanate raw material were weighed and added to the polyol, and the mixture was stirred for 10 seconds under the condition of 3000 revolutions, and then the polyisocyanate weighed therein was added. After stirring for 2 seconds, the mixture was poured into a temperature-controlled (45 ° C) iron mold.
Then, after curing for 2 minutes, the mold was removed to obtain a molded product. A test piece for a wear test was made from the obtained molded product, and a wear test was performed by the following method. The results are shown in each table. The mold release time of the molded product was measured, but all the examples were within the range of 1.5-2 minutes, and there was no problem in molding. The demolding time of Comparative Examples 1 and 2 was 2.
5 minutes and 3 minutes.

(Abrasion resistance evaluation method) From the molded product (car handle) obtained as described above, the outer peripheral length is approximately 80.
mm test pieces were cut out. Explaining the shape and dimensions of the molded product by its radial cross section, the molded product has a substantially elliptical major axis of 28 mm on the outer periphery of a hollow iron pipe (outer diameter 14 mm).
The polyurethane foam is coated so that the minor axis is 23 mm. Such a test piece is a commercially available Suga friction tester F
An abrasion test was conducted using R-2-S type (manufactured by Suga Test Instruments Co., Ltd.). The test piece was set in the tester so that the outer periphery of the test piece was in contact with the white cloth, and a load of 100 g was applied to one end of the white cloth. In this state, the surface of the test piece was rubbed with the white cloth a predetermined number of times (30,000 times, 50,000 times and 100,000 times). The abrasion resistance was evaluated by visual observation, and each was ranked. The rank was displayed at intervals of 0.5 for grades 1 to 5.
Grades with no abnormality were evaluated as grade 5, grades with advanced gloss on grade 4, grades with advanced degree of wear were grade 3 and so on.

[0021]

The polyurethane foam molded article of the present invention is manufactured using a specific polyisocyanate raw material, and is substantially excellent in abrasion resistance even when water is the sole foaming agent. Therefore, the present invention corresponds to the chlorofluorocarbon regulation, and the molded product thereof is suitably used for applications such as a handle member, a headrest and an armrest for automobiles, furniture members, etc., which are required to have wear resistance.

Table 1 Types of polyisocyanates (Examples) A B C D E F (prepolymer -) isocyanate - DOO component I-125 53 48 48 48 38 28 I-143L 18 16 16 16 14 12 PAPI-135 5 10 10 10 20 30 polyol - Le component PTMG700 - 26 - - -ー PTMG1000 24-26-28 30 PTMG1500---26-- (Total NCO% of Polyisocyanate Mixture) 22.5 20.6 21.5 22.4 20.6 19.8

[0023]

Table 3 Formulation and characteristics of molded products (Examples) 1 2 3 4 5 6 Polyisocyanate A 100-----Polyisocyanate B-100----Polyisocyanate C--100---Polyisocyanate D---100--Polyisocyanate E ----100-Polyisocyanate F-----100 Polyol P2 60 60 60 60 60 60 Polyol CPP1 40 40 40 40 40 40 MEG 7 7 7 7 7 7 Dabco 33LV 1.5 1.5 1.5 1.5 1.5 1.5 NIAX A-1 0.3 0.3 0.3 0.3 0.3 0.3 Water 0.5 0.5 0.5 0.5 0.5 0.5 (Molded product characteristics) Abrasion resistance 30,000 cycles 5 5 5 5 5 5 50,000 cycles 5 5 5 5 5 5 100,000 cycles 4.5 4.5 4.5 4.5 4.5 4.5 Compounding amount: parts by weight (however, polyisocyanate is NCO index)

Table 4 Formulation and characteristics of molded products (Examples)  7 8 9 10 11 12 13 14 Polyisocyanate C 100 100 100 100 100 100 100 100 Polyol P2 30 50 70 100 60 60 60 60 Polyol CPP1 70 50 30-40 40 40-Polyol CPP2-------40 MEG 7 7 7 7 7 7 7 7 Dabco 33LV 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 NIAX A-1 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Water 0.5 0.5 0.5 0.5 0.3 0.8 0.2 0.5 CFC-11------5-  (Molded product characteristics) Abrasion resistance 30,000 cycles 5 5 5 4.5 5 5 5 5 5 50,000 cycles 5 5 5 4 5 5 5 5 100,000 cycles 4.5 4.5 4.5 3.5 4.5 4.5 4.5 4.5  Compounding amount: parts by weight (however, polyisocyanate is NCO index)

[0026] Compounding amount: parts by weight (however, polyisocyanate is NCO index)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08G 101: 00) C08L 75:04

Claims (7)

[Claims] 1. A polyurethane foam molded article obtained by reacting polyisocyanates and polyols in the presence of a blowing agent, wherein polymethylene polyphenyl polyisocyanate is used as the polyisocyanates. Polyurethane foam molded article characterized by using a prepolymer containing a terminal isocyanate group, which is obtained by reacting an organic polyisocyanate containing as an essential component with poly (oxytetramethylene) glycol . 2. The polyurethane foam molded article according to claim 1, wherein the content of polymethylene polyphenyl polyisocyanate in the prepolymer is 2 to 30% by weight. 3. The polyurethane foam molded article according to claim 2, wherein the content of poly (oxytetramethylene) glycol in the prepolymer is 20-45% by weight. 4. A polymer polyol obtained by reacting a polyether polyol with an ethylenically unsaturated monomer is used as an essential component as a polyol.
The described polyurethane foam molded article. 5. The polyurethane foam molded article according to claim 4, wherein the proportion of polymer-polyol in the polyol is 30-70% by weight. 6. The polyurethane foam molded article according to claim 4, wherein acrylonitrile is used as an essential component as the ethylenically unsaturated monomer. 7. The polyurethane foam molded article according to claim 1, wherein the foaming agent is water.