JP3357134B2 - Method for producing polyurethane and / or polyurea molded article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Polyurethane and / or polyurea molded articles are used for seat cushions, automobile parts, electronic / electric equipment parts, etc. according to their physical properties. Application to interior materials and exterior materials as parts is progressing, and polyurethane and / or polyurea molded products having particularly fine cells are widely used for bumpers, armrests, steering wheels and the like of automobiles.

[0002]

2. Description of the Related Art Polyurethane and / or polyurea molded articles are produced by introducing a reaction mixture comprising a polyisocyanate, an active hydrogen compound, a chain extender and, if necessary, an additive into a mold capable of being sealed.

Examples of the polyisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate (hereinafter, referred to as MDI), polyphenylpolymethylene polyisocyanate (hereinafter, referred to as polymeric MDI), xylylene diisocyanate, and modified products of these polyisocyanates. However, MDI is widely used for bumpers, armrests, handles, and the like, since the molded product immediately develops its strength immediately after the reaction and has excellent physical properties.

Since this MDI is a solid at room temperature, it is usually used after being modified and liquefied. There are two types of modification: urethane modification and carbodiimide modification (or uretoimine modification). Polyisocyanates which have been successively modified or modified by both modification methods are used as a mixture. Urethane modification means that MDI is reacted with a small amount of low molecular weight diol, triol, etc.
This is a method in which a number to several tens of isocyanate groups of MDI are changed to urethane groups (JP-A-3-74357). The carbodiimide-modified (or uretimine-modified) method utilizes a reaction in which carbon dioxide is eliminated from two isocyanate groups to form a carbodiimide group, and is a method in which MDI is heated at a high temperature or reacted in the presence of a catalyst. And
This is disclosed in JP-B-45-7545, JP-A-51-12223, and the like.

The active hydrogen compound has a molecular weight of 500 to 20.
000, preferably 800 to 15,000 polyether polyols, polymer polyols, polyester polyols, polyether polyamines and the like. The chain extender is a polyhydric alcohol having a molecular weight of 62 to 500, a polyvalent amine, or the like.
4527, JP-A-57-74325, JP-B-63-47
726 and the like.

It is also known to add glass fiber, rock wool, mica or the like as a reinforcing agent and a filler in order to improve the shape retention and dimensional stability of a molded article (Plastic Age, April 1986). 119-126).
A method is also known in which most of the active hydrogen compounds are reacted with a polyisocyanate in advance to greatly improve the thermal characteristics such as the heat distortion temperature of a molded article (Japanese Patent Laid-Open No. 3-7721).

[0007]

However, such a production method requires a relatively expensive M as a polyisocyanate.
The use of DI and its modification for further liquefaction complicates the production process of polyisocyanate, causes a significant increase in cost, and is a major factor in expanding the application of molded products to new fields. Obstacles.

On the other hand, polymeric MDI is liquid at room temperature, and its cost is lower than that of MDI. Therefore, it has been considered to attempt to reduce the cost of molded articles by using this. However, the flow of the reaction mixture in the mold is considered. The mechanical properties such as elongation at break, tear strength, and abrasion resistance of the molded product, and changes in rigidity with temperature change, and physical properties such as sagging (heat sag) at high temperatures are significantly deteriorated. Only attempts have been made to add very small amounts of polymeric MDI to aid the liquefaction of the MDI, or to reduce costs knowing that these properties are impaired.

[0009]

Means for Solving the Problems The present inventor has manufactured a liquefied polyisocyanate at a relatively low cost in a simpler manufacturing process, and has further improved the mechanical and physical properties by using MDI. As a result of intensive studies on a method for producing a molded article comparable to an article, the present invention has been completed.

The present invention uses a polyisocyanate, an active hydrogen compound, a chain extender and, if necessary, an additive,
The present invention relates to a method for producing a polyurethane and / or polyurea molded product by a reaction injection molding method.

Polyisocyanates are binuclear MDs
I to 85 to 40% by weight, and a trinuclear or higher polynuclear compound to 15 to 6
Polymeric MDI containing 0% by weight and having an average functionality of 2.2 to 3.0 was prepared by adding a monofunctional active hydrogen compound such as methanol, ethanol, or isopropanol (hereinafter referred to as IP).
A. ), Aliphatic alcohols such as 2-ethylhexanol, oleyl alcohol and stearyl alcohol, aliphatic amines such as ethylamine and propylamine, N-methyl-N-ethylamine, N-methyl-N-
Modified polymer MDI whose average functionality is almost equal to that of MDI by denaturation with aliphatic secondary amines such as propylamine, aromatic alcohols such as benzyl alcohol and phenoxyethanol, or mixtures thereof. is there. The modified polymer MDI is preferably obtained by adding a monofunctional active hydrogen compound to [1000 g of polymer MDI] and adding [trinuclear or higher polynuclear compound content (wt%) × 0.015 to 0.05] mol. is there. The average functionality will be between 1.9 and 2.2. In order to further improve the liquid stability at a low temperature or to improve the physical properties of a molded product, such a modified product is further modified with urethane using a diol, a triol, or the like, heated at a high temperature, or heated in the presence of a catalyst. Or carbodiimide modification.

The chain extender is an aromatic diamine having a nucleus-substituted alkyl group, for example, diethyltoluenediamine (hereinafter referred to as DETDA) and t-butyltoluenediamine. Ethylene glycol (hereinafter, referred to as EG), diols such as 1,4-butanediol, triols such as trimethylolpropane, low-molecular-weight polyols having a molecular weight of 500 or less, and alkylene oxide adducts of ethylenediamine can also be used in combination. is there.

The active hydrogen compound has a molecular weight of 500 to 200.
And preferably 800 to 15000 polyether polyols, polymer polyols, polyester polyols and polyether polyamines.

If necessary, a catalyst, an internal mold release agent, a foam stabilizer, a foaming agent, a flame retardant, an antioxidant, and the like may be added to the polyisocyanate and / or the active hydrogen compound. The addition amount is usually 10 parts by weight or less, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total of the polyisocyanate and the active hydrogen compound. The catalyst is, for example, an organometallic compound such as dibutyltin dilaurate, or a tertiary amine such as triethylenediamine. The internal release agent is, for example, an amine solution of a fatty acid metal salt or a silicone compound. The foam stabilizer is, for example, a silicone compound. The foaming agent is, for example, air, a fluorine-containing compound (for example, Freon 11, Freon 123, Freon 141b),
Hydrocarbons (eg, pentane, cyclopentane). Further, a reinforcing filler such as glass fiber, rock wool, glass flake, mica, wollastonite and the like may be used in such a degree that the surface clarity of the molded article is not impaired. By introducing these raw materials into a mold that can be hermetically sealed using a reaction injection molding machine, a polyurethane and / or polyurea molded article having high elongation at break and high tear strength and high heat sag can be produced.

[0015]

The present invention will be described in detail with reference to Reference Examples, Examples and Comparative Examples.

Reference Example 1 1000 g of polymeric MDI having a binuclear content of 50% was heated to 60 ° C., and 71.4 g (1.18 mol) of IPA and polypropylene glycol having a hydroxyl value of 500 mgKOH / g (hereinafter referred to as PPG) 42. 5 g (0.19 mol) were added in two portions with stirring. Further, the mixture was reacted at 70 ° C. for 5 hours to obtain an isocyanate content of 2
A 2.2% homogeneous isocyanate mixture was obtained. The viscosity at 25 ° C. of this liquid was 6,200 cps.

Reference Example 2 1000 g of polymeric MDI having a binuclear content of 50% was heated to 60 ° C., and 91.7 g (1.52 mol) of IPA were added in two portions with stirring. Furthermore, at 70 ° C., 5
The reaction was carried out for a time to obtain a homogeneous isocyanate mixture having an isocyanate content of 23%. The viscosity of this liquid at 25 ° C.
It was 2300 cps.

Reference Example 3 1000 g of polymeric MDI having a binuclear content of 45% was heated to 60 ° C., and 142 g (1.09 mol) of 2-ethylhexanol was added in two portions with stirring. The mixture was further reacted at 70 ° C. for 5 hours to obtain an isocyanate content of 2
A homogeneous isocyanate mixture of 3.1% at 800 cps (25 ° C.) was obtained.

Reference Example 4 550 g of polymeric MDI having a binuclear content of 45% and M
DI 450 g was mixed to prepare a polyisocyanate having a binuclear content of 70% (polynuclear content of trinuclear or higher is 30%), and heated to 60 ° C. to 86.3 g of IPA (1.4%).
3 mol) were added in two portions with stirring. 7 more
The mixture was reacted at 0 ° C. for 5 hours to obtain an isocyanate content of 24.2%.
% Of a homogeneous isocyanate mixture was obtained. 25 of this liquid
C viscosity was 1200 cps.

Example 1 Propylene oxide (hereinafter referred to as trimethylolpropane)
Called PO. ) And ethylene oxide (hereinafter referred to as EO) (PO: EO molar ratio 83:17), and a polyether polyol 15200 having a molecular weight of 6000 obtained.
molecular weight 36 obtained by adding PO to ethylenediamine
0 g of polyether polyol, DETDA42
Then, 20 g of dibutyltin dilaurate and 20 g of a 33% dipropylene glycol solution of triethylenediamine were added, and the mixture was stirred for 30 minutes using a stirrer (rotary stirrer 525 N-1.5, rotation speed: 240 / min) to obtain a polyol. A mixture was obtained. The polyol mixture and the isocyanate mixture having an isocyanate content of 22.2% obtained in Reference Example 1 were mixed with a reaction injection molding machine (PEC-MC104R manufactured by Polyurethane Engineering Co., Ltd.) to obtain 100:
The mixture was poured into a flat mold at 70 ° C. at a weight ratio of 60 for 1 second, and after 30 seconds, the mold was removed and the width was 300 mm and the length was 700 m.
m, a molded product having a thickness of 3 mm was obtained. 120 ° C
, And then measured for physical properties. First result
See the table.

Example 2 The polyol mixture shown in Example 1 and the isocyanate mixture obtained in Reference Example 2 were mixed and injected into a mold at a weight ratio of 100: 58 using the same reaction injection molding machine as in Example 1. To obtain a molded product. After heat treating this molded article at 120 ° C. for 30 minutes, the physical properties were measured. The results are shown in Table 1.

Example 3 The polyol mixture shown in Example 1 and the isocyanate mixture obtained in Reference Example 3 were mixed and injected into a mold at a weight ratio of 100: 59 using the same reaction injection molding machine as in Example 1. To obtain a molded product. After heat treating this molded article at 120 ° C. for 30 minutes, the physical properties were measured. The results are shown in Table 1.

Example 4 The polyol mixture shown in Example 1 and the isocyanate mixture obtained in Reference Example 4 were injected into a mold at a weight ratio of 100: 55.5 using the same reaction injection molding machine as in Example 1. Thus, a molded product was obtained. After heat treating this molded article at 120 ° C. for 30 minutes, the physical properties were measured. The results are shown in Table 1.

Comparative Example 1 To 1000 g of MDI having a binuclear content of 99%, 151 g of tripropylene glycol (hereinafter referred to as TPG) was added in two portions and reacted in the same manner as in Reference Example 1 to give an isocyanate content of 22.8%. Was obtained. The viscosity at 25 ° C. was 700 cps. The polyol mixture shown in Example 1 and this liquid material were mixed with each other using a reaction injection molding machine.
A molded product was obtained by injecting into a mold at a weight ratio of 00:58. Table 2 shows the measurement results of the physical properties of the obtained molded article.

Comparative Example 2 550 g of polymeric MDI having a binuclear content of 45% and M
DI 450 g was mixed, and the content of trinuclear or higher polynuclear was 3
A 0% polyisocyanate was prepared, heated to 60 ° C., and 62 g of PPG having a hydroxyl value of 500 mg KOH / g.
(0.27 mol) was added in two portions with stirring.
The reaction was further performed at 70 ° C. for 5 hours to obtain a uniform liquid having an isocyanate content of 28%. The viscosity at 25 ° C is 120
cps. The polyol mixture shown in Example 1 and this liquid were injected into a mold at a weight ratio of 100: 48 using a reaction injection molding machine to obtain a molded product. Table 2 shows the measurement results of the physical properties of the obtained molded article. The stiffness and elongation at break were remarkably reduced only by adding 30% of polynuclear bodies of three or more nuclei.

Comparative Example 3 To 15,000 g of a polyether polyol having a molecular weight of 6000 obtained by adding PO and EO (weight ratio of PO: EO: 80:20) to trimethylolpropane, EO and PO (weight of EO and PO) were added to toluenediamine. Ratio of 46:54) to obtain a polyether polyol 600 having a molecular weight of 480.
g, 2850 g of EG, 45 g of a 32% diethylene glycol solution of triethylenediamine, 3 g of dibutyltin dilaurate, and 900 g of chlorofluorocarbon 11 were added and stirred to obtain a polyol mixture. Comparative Example 1 with this polyol mixture
100: 90 using the reaction injection molding machine with the liquid obtained in
To obtain a molded product. 3 at 120 ° C
After heat treatment for 0 minutes, the physical properties of the molded article were measured. The results are shown in Table 2. The heat sag is twice or more as compared with the embodiment.

Comparative Example 4 The polyol mixture shown in Comparative Example 3 was mixed with the isocyanate mixture obtained in Comparative Example 2 by using a reaction injection molding machine.
A molded product was obtained by injecting into a mold at a weight ratio of 0:85. After heat treating this molded article at 120 ° C. for 30 minutes, physical properties were measured. The results are shown in Table 2. Despite the increase in the normal temperature bending modulus, the heat sag is reduced by about 5 times compared to the example, and the elongation at break is also greatly reduced.

Comparative Example 5 150 g (0.67 mol) of EG was added in two portions to 1000 g of polymeric MDI having a binuclear content of 50% and reacted in the same manner as in Reference Example 1 to give an isocyanate content of 22.5.
% Liquid was obtained. The viscosity of this liquid at 25 ° C. is 33.0
00 cps. This liquid could not be used for molding due to its high viscosity.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

Conventionally, when a low molecular weight polyhydric alcohol is used as a chain extender, the rigidity dependence on temperature becomes so large that polymeric MDI which has not been suitable for use as a polyisocyanate is replaced with an aromatic diamine. It has been found that when used as a chain extender, it shows little of its disadvantages. Also, Polymeric MDI is
Due to the high functionality, it impairs the flowability of the reaction mixture and has defects such as lowering the elongation at break of molded products.
It has been found that, by adjusting the average functionality by reacting a monofunctional active hydrogen compound, a polyisocyanate which has a relatively low viscosity and gives a molded product a high elongation at break can be obtained. Furthermore, not only does it have no adverse effect on the high-temperature stability of the molded article expected to be caused by polynuclears of three or more nuclei contained in the polyisocyanate, but also it can be molded by modifying with a monofunctional active hydrogen compound. It has been found that it gives the article a higher rigidity. Using a polymeric MDI modified with such a monofunctional active hydrogen compound and an aromatic diamine chain extender, M
A molded article having various properties comparable to a molded article using DI can be manufactured at a relatively low cost.

(56) References JP-A-6-228266 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 18/00-18/87

Claims (2)

(57) [Claims] 1. A polyisocyanate, an active hydrogen compound,
In a method for producing a polyurethane and / or polyurea molded article by a reaction injection molding method using a chain extender and, if necessary, an additive, a) the polyisocyanate is a polynuclear substance having 3 or more nuclei in a range of 15 to 60. A polyisocyanate obtained by modifying a polymethylene polyphenyl polyisocyanate containing by weight with a monofunctional active hydrogen compound, b)
A process for producing a polyurethane and / or polyurea molded product wherein the chain extender is an aromatic diamine having a nucleus-substituted alkyl group. 2. A modified polyisocyanate is prepared by adding a monofunctional active hydrogen compound to a polymethylene polyphenyl polyisocyanate in an amount of [polynuclear content of 3 or more nuclei (% by weight) × 0.015 to 0.05] mol per 1000 g of polymethylene polyphenyl polyisocyanate. The method for producing a polyurethane and / or polyurea molded product according to claim 1, wherein the polyurethane and / or polyurea molded product is modified by additionally reacting.