JPH0721033B2 - Composition used for producing polyurethane resin molded article - Google Patents

Description

Detailed Description of the Invention

[0001]

[Industrial application] Polyurethane resin molded products are used for seat cushions, automobile parts, electronic device parts, electric device parts, etc. according to their physical properties. As a result, application to interior materials and exterior materials is progressing. Polyurethane resin moldings having a foamed central portion and a non-foamed or skin portion having fine air bubbles are used for automobile bumpers, armrests, steering wheels, and the like.

[0002]

2. Description of the Related Art A polyurethane resin molded article is prepared by introducing a reaction mixture consisting of polyisocyanate, a compound containing at least two hydrogen atoms reactive with an isocyanate group (hereinafter referred to as polyol), and an additive into a hermetically sealable mold. Is manufactured by

The reaction mixture hardens in the mold and is removed as a molded article. The mold is made of a material having high thermal conductivity in order to control the reaction temperature, and a metal mold (hereinafter referred to as a mold) is generally used.

In order to prevent the polyurethane resin molded product from sticking to the surface of the mold, a method of applying a release agent such as wax, metallic soap, oil and fat to the surface of the mold is usually adopted. In this case, a thin film having a small surface tension is formed between the molded product and the surface of the mold, and this thin film prevents the molded product from sticking to the surface of the mold, so that the molded product can be easily taken out. .

[0005]

However, in this method, a new release agent must be applied every time molding is performed, and the sieving release agent remaining on the mold surface must be removed at regular intervals. I won't. This requires considerable manpower and time.

On the other hand, a method of adding a compound having a releasing property to a reaction mixture has also been studied. A releasing agent applied to the surface of a mold is called an external releasing agent, and a releasing agent added to a reaction mixture is called a releasing agent. It is called an internal release agent. To provide a method for producing a polyurethane resin molded product, which can omit the application of an external release agent or the cleaning of the mold surface every time molding is performed, reduce the operation in the molding process, and contribute to the improvement of productivity. Is the object of the present invention.

[0007]

Means for Solving the Problems The present invention provides a polyisocyanate, a polyol, a cross-linking agent, a catalyst, and an internal mold release agent, which are coated with an external mold release agent in advance.
Further, an internal mold release agent used in a method for producing a polyurethane resin molded article by introducing a reaction mixture containing a foaming agent and an auxiliary agent, and polyoxypropylene polyamine and polyoxyethylene polyamine which are equimolar or more with zinc stearate. , Isophoronediamine or 1,8-diamino-
It relates to a composition consisting of p-menthane.

As the polyisocyanate used in the present invention, diphenylmethane diisocyanate, a mixture of diphenylmethane diisocyanate and its homologues, modified isocyanates obtained by reacting these polyisocyanates with polyfunctional hydroxyl group-containing compounds or modified by carbodiimidization, There is a mixture of these.

As the polyol, a polyfunctional hydroxyl group-containing compound such as glycerin or an amino group- and hydroxyl group-containing compound such as triethanolamine or an amino group-containing compound such as diaminotoluene is added to an alkylene oxide such as ethylene oxide or propylene oxide. A polyether polyol having 2 to 6 hydroxyl groups in the added molecule and having an average hydroxyl equivalent of 1000 to 3000, or a polymer polyol obtained by polymerizing a vinyl compound in the polyether polyol is used.

As the cross-linking agent, low molecular weight diols such as ethylene glycol, propylene glycol and butanediol are used. Amino alcohols such as triethanolamine, amino group-containing compounds such as diethyltoluenediamine or alkylene oxides are added to these compounds. Also used are polyols and the like.

As the catalyst, tertiary amines such as triethylenediamine and dimethylethanolamine, and organometallic compounds such as dibutyltin dilaurate are used.

As the foaming agent, water, halogenated hydrocarbon, nitrogen or the like is used. As the auxiliaries, various agents such as a bubble regulator, a discoloration preventing agent, a flowability improving agent, and a coloring agent are used as necessary.

The required amounts of these crosslinking agents, catalysts, blowing agents and auxiliaries may be added to the polyol in advance, or may be added during the reaction with the polyisocyanate.

The external release agent has a solid content melting point of 100.
A wax-based mold release agent having a temperature of ℃ or more is preferable.

Zinc stearate used as an internal mold release agent is a solid having a melting point of about 120 ° C., has poor solubility in polyol, and precipitates and separates when left at room temperature. To improve the compatibility with polyols, zinc stearate
It is advisable to add it to the polyol by mixing it with an equimolar amount or more of polyoxypropylene polyamine, polyoxyethylene polyamine, isophorone diamine or 1,8-diamino-p-menthane.

Zinc stearate is used in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the polyol, and polyoxypropylene polyamine, polyoxyethylene polyamine, isophorone diamine or 1,8-diamino-p-menthane is used. Within the range of 1 to 10 parts by weight, it is preferable to use equimolar or more with zinc stearate. Polyoxypropylene polyamine, polyoxyethylene polyamine, isophorone diamine or 1,8-diamino-p-menthane in an equimolar amount or more with zinc stearate is added in a predetermined amount to the polyol in advance, or at the time of reaction with polyisocyanate. Add.

[0017]

EXAMPLES The present invention will be described in detail with reference to Examples and Comparative Examples. The parts are parts by weight.

Examples 1 to 4 100 parts of a polyether polyol having an OH value of 24 mgKOH / g obtained by adding ethylene oxide and propylene oxide to glycerin, 20 parts of ethylene glycol, 0.6 part of triethylenediamine, and dibutyltin dilaurate of 0.
05 parts, 3 parts Freon-11 and zinc stearate and polyoxypropylene diamine (average molecular weight about 40
0) or a polyol component in which a mixture of 1,8-diamino-p-menthane is well mixed, and 116 parts of a diphenylmethane diisocyanate derivative (a mixture of a urethane modified product and a carbodiimide modified product) having an isocyanate group content of 26.5%. The reaction mixture was coated with a wax release agent (Rimurikei B-269 manufactured by Chukyo Yushi Co., Ltd.) in advance and introduced into a U-shaped mold made of aluminum whose temperature was set to 80 ° C. This mold has a length of 40 cm, a width of 20 cm, and a depth of 20 cm.

After about 30 seconds, the mold was opened to obtain a U-shaped molded product. Thereafter, the same operation as described above was repeated without applying the external release agent and cleaning the surface of the mold, and the number of times until the mold could not be removed was examined.

Comparative Examples 1 to 2 (1) Example in which zinc stearate was not added, (2) Example in which only zinc stearate was added (Zinc stearate is obviously suspended in the polyol component. (3) An example in which a mixture of zinc stearate and polyoxypropylene diamine (average molecular weight of about 2000) was added (the polyol component to which this mixture was added was slightly cloudy), (4) External mold release An example using a U-shaped metal mold made of aluminum not brushed with the agent is shown. The amount of zinc stearate, polyoxypropylene diamine or 1,8-diamino-p-menthane added, the type of external release agent brushed on the U-shaped mold in advance, and the number of times of repeated demolding are shown in the table. It is as follows.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

EFFECT OF THE INVENTION A reaction mixture consisting of polyisocyanate, a polyol and an additive is added as an internal mold releasing agent in an amount of equimolar or more with zinc stearate, such as polyoxypropylene polyamine, polyoxyethylene polyamine, isophorone diamine or 1,8-. By adding the mixture with diamino-p-menthane, the mold release property of the polyurethane resin molded product is improved, and the work of applying the external release agent is greatly reduced.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location // B29K 75:00 (72) Inventor Shinji Nishikawa 3-13-26 Kukuchi, Amagasaki City, Hyogo Sumitomo Bayer Urethane Co., Ltd. In-house (72) Inventor Exit M. 3-13-26, Kukuchi, Amagasaki City, Hyogo Prefecture Sumitomo Bayer Urethane Co., Ltd. Examiner Yoshihiro Fuji (56) Reference JP-A-56-106915 (JP, A) JP-A-60 -500418 (JP, A)

Claims (1)

[Claims] 1. A molding die preliminarily coated with an external release agent,
An internal mold release agent used in a method for producing a polyurethane resin molded article by introducing a reaction mixture comprising a polyisocyanate, a polyol, a crosslinking agent, a catalyst and an internal mold release agent, and if necessary, a foaming agent and an auxiliary agent. Yes, polyol 10
0.5 to 5 parts by weight of zinc stearate with respect to 0 parts by weight, and polyoxypropylene polyamine, polyoxyethylene polyamine, isophorone diamine in the range of 1 to 10 parts by weight which is equimolar or more to zinc stearate. Alternatively, a composition comprising 1,8-diamino-p-menthane.