JP3311846B2 - Method for producing polyurethane / polyurea molded products - Google Patents

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 / polyurea molded article having a dense skin without using a halogenated hydrocarbon blowing agent. It is used for wheels, horn pads, console boxes or automobile exterior materials such as bumpers and spoilers.

[0002]

2. Description of the Related Art In a process for producing a polyurethane / polyurea molded product having a dense skin, a low-boiling inert organic solvent, generally a halogenated hydrocarbon, is used as a foaming agent. However, the use of halogenated hydrocarbons, especially chlorofluorocarbons, is being restricted due to environmental problems such as depletion of the ozone layer.

[0003]

In order to produce a polyurethane / polyurea molded product having a dense skin without using a halogenated hydrocarbon, a method in which a low-boiling hydrocarbon such as pentane or hexane is used as a blowing agent. Alternatively, a method using carbon dioxide gas generated from the reaction between water and polyisocyanate has been proposed (Japanese Patent Laid-Open No. Hei 5-18654).
No. 8, JP-A-3-152160). However, since the boiling point of low-boiling hydrocarbons is below room temperature, there is a great risk of fire, and considerable countermeasures are required. On the other hand, when water is used as a foaming agent, the amount of water used is as small as 1% by weight or less, so that compared with the case where a relatively large amount of halogenated hydrocarbon is used as the foaming agent, an active hydrogen compound, a chain extender, and a catalyst are used. The viscosity of a polyol mixture composed of such as above tends to be relatively high, and modification of molding equipment is required, or the mixing property at the time of molding with a polyisocyanate tends to decrease. In addition, when the halogenating hydrocarbon is replaced with water as the blowing agent, the molding shrinkage of the molded product is generally reduced, so that the size of the molded product is increased. In some cases, the mold needs to be modified depending on the application.

[0004] The present inventors have conducted intensive studies on a method for producing a polyurethane / polyurea molded article having a dense skin using water as a foaming agent, and as a result, the present invention has been completed.

[0005]

The present invention uses a polyisocyanate, an active hydrogen compound, a chain extender, a catalyst, water as a foaming agent and, if necessary, auxiliaries such as a pigment, a foam stabilizer and a filler. And has a dense skin and a density of 0.3-1.
In a method for producing a polyurethane / polyurea molded product of 1 g / cm ³ , a hydrocarbon having 10 to 16 carbon atoms is added in a range of 1 to 10% by weight based on the whole raw material, and the active hydrogen compound has three functional groups. The present invention relates to a method for producing a polyurethane / polyurea molded product, which is a polyether polyol having a molecular weight of 5,000 to 8,000 and containing 16 to 25% of a polyoxyethylene chain.

Polyisocyanates are aromatic polyisocyanates having two or more isocyanate groups, for example,
Diphenylmethane diisocyanate (hereinafter referred to as MDI), polymethylene polyphenyl polyisocyanate, urethane-modified, carbodiimide-modified, biuret-modified, isocyanurate-modified and the like, and mixtures thereof. The number of functional groups is 1.
9 to 2.9, preferably 2 to 2.5.

The active hydrogen compound has three functional groups, has a molecular weight of 5,000 to 8,000, and has one polyoxyethylene chain.
It is a polyether polyol containing 6 to 25%. When a bifunctional polyether polyol is used, the molded article tends to swell after demolding, and in order to avoid such swelling, the demolding time needs to be lengthened, resulting in reduced productivity. In the case of a polyether polyol having four or more functional groups having a large molecular weight, the viscosity of the polyol mixture to which a chain extender, a catalyst, and the like are added increases, the flow resistance in the molding machine increases, and the miscibility with the polyisocyanate decreases. Therefore, the possibility of poor mixing trouble increases. further,
In the case of a polyether polyol having four or more functional groups having the same molecular weight, the viscosity is equivalent to that of a polyether polyol having three functional groups, but expansion of the molded product is also observed after demolding.

The hydrocarbon having 10 to 16 carbon atoms is decane,
Examples include paraffins such as dodecane and tridecane, linear olefins such as decene, dodecene, tetradecene, and hexadecene; branched olefins such as triisobutylene and propylene tetramer; and alkylbenzenes such as butylbenzene and tetramethylmenzene. Hydrocarbons having a relatively high flash point and low odor have 12 to 14 carbon atoms. Hydrocarbons having 9 or less carbon atoms have a low flash point and a strong smell, and hydrocarbons having 17 or more carbon atoms are not suitable because both have no effect on molding shrinkage. The hydrocarbon is added in the range of 1 to 10% by weight based on the whole raw material.

The chain extender is ethylene glycol, 1,4
-Butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, 2,2,4
Diols such as trimethyl-1,3-pentanediol, triols such as glycerin and trimethylolpropane, aliphatic diamines such as ethylenediamine, propylenediamine, diaminocyclohexane and isophoronediamine, triethanolamine, diethanolamine,
Amino alcohols such as ethanolamine and diisopropanolamine, 1,3,5-triethyl-2,6-diaminobenzene, 1-methyl-3,5-diethyl-2,
4-diaminobenzene, 1-methyl-5-t-butyl-
Aromatic diamines such as 2,4-diaminobenzene. The amount used is 30% by weight or less of the active hydrogen compound,
Preferably it is 5 to 20% by weight.

[0010] The blowing agent is water. The amount used is 0.2 to 0.7% by weight of the active hydrogen compound. Carbon dioxide generated from the reaction between water and polyisocyanate is used for foaming. It is also possible to use a gas loading technique in which air, nitrogen, carbon dioxide gas or the like is blown into the raw material in advance and then molded.

The catalyst is triethylenediamine, dimethylethanolamine, bis (2-dimethylaminoethyl)
Ether or a tertiary amine compound such as diazabicycloundecene or a salt thereof, or an organometallic compound such as tin octoate or dibutyltin dilaurate; the amount of use is 0.01 to 3% by weight of the active hydrogen compound; is there.

In addition, auxiliary agents such as a pigment, a foam stabilizer (eg, a silicone compound), and a filler (eg, zeolite) are used as needed.

The polyurethane / polyurea molded article having a dense skin of the present invention can be produced by any molding method, but it is preferable to use a reaction injection molding method. If the raw materials other than the above are mixed and injected together with the polyisocyanate into a mold that can be hermetically sealed at a mixing ratio of 100/25 to 100/150, and then reaction-cured, the desired molded product can be manufactured.

The obtained molded article has a dense skin and has a density of 0.3 to 1.1 g / cm ³ , preferably 0.1 to 0.1 g / cm ³ .
5 to 1.0 g / cm ³ .

[0015]

【Example】

Example 1 Hydroxyl value 28 mgKOH / g, number of functional groups 3, molecular weight 60
To 86 parts by weight of a polyether polyol having 22% of polyoxyethylene chains, 5.5 parts by weight of ethylene glycol, 5 parts by weight of triisobutylene, 0.3 parts by weight of water, and 1.5% of a 33% solution of triethylenediamine in dipropylene glycol were added. Parts by weight, 0.01 parts by weight of dibutyltin dilaurate, 70 parts of bis (2-dimethylaminoethyl) ether
0.5 parts by weight of a 2% by weight dipropylene glycol solution and 2 parts by weight of a pigment were added and stirred to obtain a polyol mixture. 35
The polyol mixture heated to 30 ° C. and the glycol-modified MDI heated to 30 ° C. were mixed at a mixing ratio of 100/45 using a reaction injection molding machine (HK-165 manufactured by Henneke).
With a discharge pressure of 150 kg / cm ² and a discharge rate of 500 g / sec, 5
Injected into a flat steel mold heated to 5 ° C. over 2.5 seconds, demolded after 70 seconds, width 300 mm, length 6
A molded product having a thickness of 00 mm, a thickness of 10 mm, and a density of 0.7 g / cm ³ was obtained. Table 1 shows the physical properties of the obtained molded article.

Example 2 A molded article was obtained in the same manner as in Example 1 except that decane was used instead of triisobutylene. Table 1 shows the physical properties of the obtained molded article.

Example 3 The procedure of Example 1 was repeated, except that 10 parts by weight of dodecene was used instead of 5 parts by weight of triisobutylene, and the mixing ratio between the polyol mixture and the polyisocyanate was 100/43. A molded product was obtained. Table 1 shows the physical properties of the obtained molded article.

Example 4 The amount of water in Example 1 was increased to 0.5 parts by weight, and the mixing ratio of the polyol mixture and the isocyanate was 100 / 48.5.
Then, a molded article having a density of 0.4 g / cm ³ was obtained in the same manner as in Example 1 except that the injection time was changed to 1.5 seconds. Table 2 shows the physical properties of the obtained molded article.

Comparative Example 1 A molded article was obtained in the same manner as in Example 1 except that triisobutylene was not added and the mixing ratio between the polyol mixture and the polyisocyanate was 100/47. Table 2 shows the physical properties of the obtained molded article.

Comparative Example 2 Octadecene 10 was used instead of triisobutylene 5 parts by weight.
A molded product was obtained in the same manner as in Example 1 except that the parts by weight were used. Table 2 shows the physical properties of the obtained molded article.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

According to the present invention, in the production of a polyurethane / polyurea molded product, the addition of a hydrocarbon having 10 to 16 carbon atoms lowers the viscosity of the raw material and improves the mixing properties and flowability. It has been found that the molding shrinkage can be adjusted according to the amount, the surface of the molded product is always dried, and there is no stickiness as in the case where a usual plasticizer is added. Further, by adding a hydrocarbon having 10 to 16 carbon atoms, a molded article having a molding shrinkage similar to that of the conventional halogenated hydrocarbon foam can be produced even when water foaming is performed.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kouji Nakatani 3-13-26 Kuguchi, Amagasaki-shi, Hyogo Sumitomo Bayer Urethane Co., Ltd. (56) References JP-A-6-87945 (JP, A) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 18/00-18/87 C08J 9/00-9/14 C08L 75/04-75/12

Claims (1)

(57) [Claims] 1. A polyisocyanate, an active hydrogen compound,
Using a chain extender, a catalyst, water as a foaming agent and, if necessary, auxiliaries such as a pigment, a foam stabilizer, a filler, etc., it has a dense skin and a density of 0.3 to 1.1 g / cm. ^In the method for producing a polyurethane / polyurea molded product of No. ³ , a hydrocarbon having 10 to 16 carbon atoms is used in an amount of 1 to 10% by weight based on the whole raw material
In which the active hydrogen compound has three functional groups, has a molecular weight of 5,000 to 8,000, and has a polyoxyethylene chain of 16
A method for producing a polyurethane / polyurea molded product, which is a polyether polyol containing up to 25%.