JPH06322057A - Molded polyurethane foam - Google Patents

Abstract

PURPOSE:To obtain the subject foam having a short mold release time and excellent wear resistance. CONSTITUTION:This polyurethane foam is obtained by reacting a polyisocyanate with a polyol in the presence of water as a blowing agent and a catalyst. The polyisocyanate is an isocyanate-terminated prepolymer obtained by reacting an organic poly-isocyanate essentially consisting of polymethylenepolyphenylene polyisocyanate with poly(oxtetrametylene) glycol, and the catalyst essentially consists of an organotin compound. This foam can be desirably used in applications such as automotive and furniture members such as steering wheels, headrests and armrests which need be wear-resistant.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art The production of integral skin foams having a dense skin is well known, and the products are widely applied to automobile parts (in particular, steering wheel, headrest, armrest, etc.) and furniture. In such 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. It is considered that the formation of this skin layer contributes to demolding time such as reaction injection molding and abrasion resistance of the product.

[0003]

In recent years, CFCs have been pointed out as a cause of ozone layer depletion of 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 a substitute for CFCs, but in the conventional technology, the demolding time tends to be longer when water is foamed alone than when it is foamed using CFCs. The resulting foam has a problem that a skin layer is hard to be formed and abrasion resistance is poor. The present invention has solved the above problems,
It is an object of the present invention to provide a polyurethane foam molded product having a short demolding time and excellent wear resistance.

[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 a catalyst, and completes the present invention. Came to. That is, the gist of the present invention is to provide a polyurethane foam molded article obtained by reacting polyisocyanates and polyols in the presence of water as a blowing agent and a catalyst, wherein (1) the polyisocyanates are polymethylene polyphenylene poly Use of a terminal isocyanate group-containing prepolymer obtained by reacting an organic polyisocyanate containing isocyanate as an essential component with poly (oxytetramethylene) glycol, and (2) using an organic tin compound as an essential component as a catalyst A polyurethane foam molded article characterized by

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

As the organic polyisocyanate, polymeric MDI is used as an essential component, and as other polyisocyanates used in combination, aliphatic, cycloaliphatic,
Those known in the polyurethane or polyurea industry such as araliphatic or aromatic polyisocyanates are used. Suitable organic polyisocyanates include 1,6
-Hexamethylene diisocyanate, cyclohexane-
1,4-diisocyanate, 1,4-xylylene diisocyanate, 2,4-toluene diisocyanate, 2,
6-toluene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, polymeric MDI or urethane, urea, biuret, carbodiimide, uretonimine or modified polyisocyanate modified by the introduction of isocyanurate residues. , These are used alone or as a mixture. Among these organic polyisocyanates, it is particularly preferable to use an aromatic polyisocyanate as an essential component, and representative examples thereof include MDI isomers, that is, 4,4′-diphenylmethane diisocyanate and 2,4-diphenylmethane diisocyanate. And modified products thereof, mixtures thereof and the like.

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 to
The one of 3,000 is used. In the production of the prepolymer of the present invention, those having an average molecular weight of 500 to 2,400 are preferable.

The PTMG prepolymer of the present invention is prepared by heating an excess amount of 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 to 28% by weight, and the PTMG content is 10 to 50% by weight, preferably 20 to 45% by weight.

The content of the polymeric MDI in the PTMG prepolymer of the present invention is 1 to 40% by weight, preferably 2 to 30% by weight, more preferably 5 to 20% by weight.
It is said that

Examples of the polyols of the present invention include:
Alkylene oxides (ethylene oxide, propylene oxide, butylene oxide, etc.) are used as low molecular weight polyols (ethylene glycol, propylene glycol, glycerin, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol, sucrose, etc.) and polyamines (ethylenediamine, ethylenediamine,
Diethylenetriamine, tolylenediamine, xylylenediamine, piperazine, N-N dimethylaminoalkylamine, etc.) added polyether polyol, polyether polyol and ethylenically unsaturated monomer (acrylonitrile, styrene, butadiene, methyl methacrylate, Acrylic amide, vinyl acetate, etc.)-Reacted polymer polyol, 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, a new finding has been found that a polymer polyol is suitable from the viewpoint of improving the moldability and abrasion resistance which are the objects of the present invention. As a suitable polymer polyol, one using acrylonitrile as an ethylenically unsaturated monomer is preferable, and examples thereof include acrylonitrile alone or a copolymer of acrylonitrile and styrene. . However, although the use of polymer polyol is advantageous for improving wear resistance, it has a high viscosity,
The amount used is determined in consideration of moldability and the like. In the present invention, in the polyols, 25 to 80% by weight, preferably 30 to 70% by weight, more preferably 35 to 6% by weight.
It is set to 0% by weight.

As the foaming agent of the present invention, water alone or a mixture of water and CFCs is used, but water alone is preferred. The amount of water used is 0.05 to 5 parts by weight, preferably 0.1 to 3 parts by weight, and more preferably 0.3 to 2 parts by weight with respect to 100 parts by weight of polyols.
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, it is necessary to use an organic tin compound as an essential component as a catalyst. Examples of suitable organotin compounds include dibutyltin dilaurate,
Dibutyltin diacetate, dihexyltin diacetate,
Examples include dimethyltin dimercaptide, dibutyltin dimercaptide, dioctyltin dimercaptide, di-2-ethylhexyltin oxide, stannous octoate, and stannous oleate. Among these, mercaptide-based tin compounds such as dibutyltin dimercaptide, which are excellent in hydrolysis resistance, are preferable. The amount of the organotin compound used is 0.5 parts by weight or less, preferably 0.01 to 0.5 parts by weight, and more preferably 0.0 to 100 parts by weight of the polyols.
3 to 0.1 parts by weight.

In the present invention, an amine compound can be used in combination with the organotin compound as a catalyst. Examples of suitable amine compound catalysts include trialkylamines such as trimethylamine and triethylamine, multi-membered ring amines such as N-alkylmorpholine, and ethers such as 2,2′-bis (dimethylamino) diethyl ether. Examples thereof include 1,4-dimethylpiperazine, triethylenediamine, N, N, N ′, N′-tetramethyl-1,3-butanediamine, and aliphatic polyamines such as N-methyldiethanolamine. The amine compound catalyst is used in an appropriate amount within a known range.

In the present invention, a crosslinking agent is appropriately used. Suitable crosslinkers include triethanolamine,
Amine type low molecular weight polyol 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 in combination. The amount of the crosslinking agent used varies depending on the type of the crosslinking agent, but is usually 2 to 20 parts by weight, preferably 3 to 10 parts by weight, based on 100 parts by weight of the polyols.

In the present invention, in addition to the above-mentioned materials, various additives such as an emulsifier, a stabilizer, a surfactant, a filler, a colorant and an oxidation stabilizer can be used if necessary. The polyurethane foam molded article of the present invention can be manufactured by a conventionally known molding method such as a reaction injection molding method.

[0017]

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) Polyisocyanates 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%) was selected, and as the polyol component, the average molecular weight was 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 polyether polyol having an average equivalent number of 1600 (EO content: 14% , Hereinafter referred to as Polio P1). Using the above-mentioned components of the organic polyisocyanate and the polyol, a terminal NCO group-containing prepolymer was produced by a conventional method. The compositions of the obtained prepolymer and polyisocyanates (mixture) are shown in Tables 1 and 2.

(2) Polyols Polyol P2: a 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 polyether polyol 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 the above-mentioned polyol P2 with acrylonitrile (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
0) was copolymerized (solid content: 20%).

(3) Additive Catalyst: Tin catalyst: Dibutyltin dimercaptide (FOMR)
EZ UL-1: manufactured by Wisco) Amine-based catalyst 1: Triethylenediamine (33% solution of dipropylene glycol) (Dabco 33LV: manufactured by Air Product Co.) Amine-based catalyst 2: bis (dimethylaminoethyl) ether ( NIAXA-1: Union Carbide Co., Ltd.) Crosslinking agent: monoethylene glycol (MEG) Blowing agent: water, trichlorofluoromethane (CFC-1)
1)

Examples 1 to 18 and Comparative Examples 1 to 3 Polyurethane foam molded articles (in accordance with the compounding recipes shown in Tables 3 to 6 (the polyisocyanate content in the tables is represented by NCO index)) were prepared as follows. Car handle)
Was manufactured. All other components except the polyisocyanate raw material are weighed and added to the polyol, and after stirring for 10 seconds under the condition of 3000 rpm, the polyisocyanate weighed therein is added and after stirring for 3 seconds under the same condition. The mixture was poured into a temperature-controlled (50 ° C) iron mold. Cure time is 180 seconds, 150 seconds, 120 seconds,
90 seconds and 5 seconds of 5 seconds, after the prescribed cure,
The molded product was immediately demolded, and the properties of the molded product (swelling, peeling of the skin, etc.) were evaluated, and this was taken as the evaluation of the demolding time. The results (normal: ◯, almost normal: Δ, abnormal: x) are shown in each table. Further, a test piece for a wear test was made from a molded product obtained normally, and a wear test was conducted by the following method. The results are also shown in each table.

(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 has a white cloth (canvas # 10) on its outer circumference.
Was set in the tester so that they would come into contact with each other, 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 visually and each was ranked. As for the rank, 1 to 5 grades were displayed at 0.5 intervals. Grades with no abnormalities were evaluated as grade 5, grades with advanced gloss on grade 4 and grades with increased degree of wear were grade 3 and so on.

[0023]

EFFECTS OF THE INVENTION The polyurethane foam molded article of the present invention uses a compounding recipe in which a specific polyisocyanate raw material and an organic tin compound are essential components of a catalyst, and in practice water is the only blowing agent and a short defoaming agent is used. Manufacturing in mold time is possible, and the molded product has excellent wear resistance. Therefore, the present invention corresponds to the chlorofluorocarbon regulation, and the molded product 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 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 component PTMG700 - 26 - - chromatography - PTMG1000 24 -26-28 30 PTMG1500 --- 26- ( total NCO% of polyisocyanate mixture) 22.5 20.6 21.5 22.4 20.6 19.8

[0025]

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 Fomrez UL-1 0.07 0.07 0.07 0.07 0.07 0.07 Dabco 33LV 1.5 1.5 1.5 1.5 1.5 1.5 NIAX A-1 0.4 0.4 0.4 0.4 0.4 0.4 Water 0.5 0.5 0.5 0.5 0.5 0.5 Demolding time 180 seconds ○ ○ ○ ○ ○ ○ 150 seconds ○ ○ ○ ○ ○ ○ 120 seconds ○ ○ ○ ○ ○ ○ 90 seconds △ ○ ○ ○ ○ ○ 60 seconds × △ △ △ △ △ ○ Abrasion resistance 30,000 times 5 5 5 5 5 5 50,000 times 5 5 5 5 5 5 100,000 times 4.5 4.5 4.5 4.5 4.5 4.5

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 Fomrez UL-1 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 Dabco 33LV 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 NIAX A-1 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Water 0.5 0.5 0.5 0.5 0.3 0.8 0.2 0.5CFC-11------5- Demolding time 180 seconds ○ ○ ○ ○ ○ ○ ○ ○ 150 seconds ○ ○ ○ ○ ○ ○ ○ ○ 120 seconds ○ ○ ○ △ ○ ○ ○ ○ 90 seconds ○ ○ △ × ○ ○ △ ○60 seconds △ △ × × △ △ × △ Abrasion resistance 30,000 cycles 5 5 5 4.5 5 5 5 5 50,000 cycles 5 5 5 4 5 5 5 5100,000 times 4.5 4.5 4.5 3.5 4.5 4.5 4.5 4.5 4.5

[0028]

[0029]

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

Claims (6)

[Claims] 1. A polyurethane foam molded article obtained by reacting polyisocyanates and polyols in the presence of water as a blowing agent and a catalyst, wherein (1) polymethylene polyphenylene polyisocyanate is essential as polyisocyanates. A terminal isocyanate group-containing prepolymer obtained by reacting an organic polyisocyanate as a component with poly (oxytetramethylene) glycol is used, and (2) an organotin compound is used as an essential component as a catalyst. Polyurethane foam molded product. 2. The polyurethane foam molded article according to claim 1, wherein the proportion of polymethylene polyphenylene polyisocyanate in the prepolymer is 2 to 30% by weight. 3. The polyurethane foam molded article according to claim 1, wherein the content of poly (oxytetramethylene) glycol in the prepolymer is 10 to 50% by weight. 4. The polyurethane foam molded article according to claim 1, wherein the proportion of the organotin compound used is 0.01 to 0.5 parts by weight based on 100 parts by weight of the polyols. 5. The polyurethane foam molded article according to claim 1, wherein a polymer polyol obtained by reacting a polyether polyol and an ethylenically unsaturated monomer is an essential component as the polyol. 6. The polyurethane foam molded article according to claim 5, wherein the proportion of the polymer polyol in the polyols is 30 to 70% by weight.