JPS5842613A - Production of urethane foam article - Google Patents

Abstract

PURPOSE:To obtain a semirigid urethane foam article, such as car interior part, having a hardness which is lowered without detriment to its mechanical properties, by adding a specified ester compound in producing a urethane foam. CONSTITUTION:The titled article is prepared by mixing (A) a polyol component (e.g., polyether-polyol prepared by adding ethylene oxide to glycerol) with (B) a crosslinking agent (e.g., ethylene glycol), (C) a catalyst (e.g., triethanolamine), (D) a blowing agent (e.g., trichloromonofluoromethane), (E) an ester compound selected from the group consisting of phthalates, adipates, trimellitates and phosphates and (F) a polyisocyanate (e.g., methylene diisocyanate) and molding and foaming the mixture in a mold. Component E is added in an amount of 5- 100pts.wt. per 100pts.wt. component A.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for manufacturing semi-rigid urethane foam products.

Here, the case where a urethane foam product is molded by the integral skin method will be explained as an example, but the method is not limited to this.

Urethane foam products using the above integral skin method can be integrally molded with the skin layer and the foam layer, and have excellent elasticity and tactility, so they are often used in automotive interior parts such as steering wheels, crash pads, headrests, armrests, etc. has been done.

However, in recent automobile interior parts, it is sometimes necessary to make the polyurethane portion thinner from the standpoint of design and weight reduction. When this polyurethane portion is made thinner, the ratio of the dense skin layer to the foam layer increases relatively, and there is a risk that the overall hardness will be high and the tactile sensation will be deteriorated.

In this case, in order to reduce the hardness of the polyurethane and obtain a flexible skin layer, it is possible to reduce the amount of crosslinking agent in the polyurethane to lower the crosslink density. However, at the same time, mechanical strength such as tensile strength is significantly reduced, making it impractical.

In view of the above, an object of the present invention is to provide a method for manufacturing a urethane foam product that can reduce the hardness of polyurethane without substantially reducing mechanical strength.

In order to achieve the above object, this invention applies an ester compound selected from a specific group to a polyol/component of S to 10 OPH when molding a urethane foam product.
Do this by adding EL.

The present invention will be explained in detail below.

The polyurethane formulation of this invention is the same as a normal semi-rigid urethane foam formulation, except that a selected specific ester compound is added, and the specific details are as follows.

A. Polyol component (1) Polyether polyol: Polyether polyol with a molecular weight of 2000 to 7000, which is obtained by adding alkylene oxide such as ethylene oxide or propylene oxide to a low-molecular polyol such as glycerin or trimethylolpropane. .

(2) Polymer polyol type: A polymer polyol with a molecular weight of 3000 to gO00, which is obtained by graft polymerizing a vinyl monomer such as acrylic or styrene to the above polyether polyol.

(3) Polyester-based...ethylene glycol,
A polyester polyol with a molecular weight of 1000 to 500 obtained from a polyhydric alcohol such as pyrene glycol or diethylene glycol, and a dibasic acid such as succinic acid, adipic acid, phosphoric acid, azelaic acid, or sebacic acid.

B. Crosslinking agent (1) Polyhydric alcohol: ethylene glycol, diethylene glycol, /lI-butanediol, propylene glycol-hexanetriol, etc.

(2) Polyamine polyol: A product obtained by adding alkylene oxide to ethylene diamine, etc.

(3) Amino alcohol: jetanolamine, triethanolamine, etc.

(4) Aromatic amines: methylenebis-orthochloroaniline, etc.

C. Catalyst: triethylamine, N-methylmorpholine, N,N-dimethylcyclohexylamine, N,
N-dimethylethanolamine, N,N-diethylethanolamine, pentamethyldiethylenetriamine, triethylenediamine, diptyltin dilaurate, stannous octylate, gobalt octylate, and the like.

D. Foaming agent: Trichloromonofluoromethane (
-yvoniy-//),)lichlorotrifluoroethane:
y (7v on-//3) (for integral skin) or water, methylene chloride, etc.

E. Ester compound (1) Phthalate ester...dibutyl phthalate,
Diheptyl phthalate, dioctyl phthalate, phthalundecyl, ditridecyl phthalate, etc.

(2) Adipate esters: dioctyl adipate, diisodecyl adipate, etc.

(3) Trimeritic acid S
Octyl acid, etc.

(4) Lysate ester...tricresyl phosphate, etc.

Seven or more compounds selected from the ester compound group (E) are added to the polyol component A. 3 to
10 OPHR, preferably 10-7.

5 - Blend PHR. Here, when 5 PH is less than 111, no effect of reducing the hardness of the molded article is obtained, and when it exceeds 10 OPHR, moldability is reduced.

F. Polyisocyanate (usually methylene diisocyaner) (MDI), carbodiimide-modified MDI (liquid MDI), and MDI prepolymers obtained by reacting these with low molecular weight polyols are used.

The urethane foam product of the present invention is usually molded by RIM molding or low pressure foaming.

Hereinafter, in order to confirm the effects of the present invention, comparative examples are given together with examples, and the physical property test results are shown in Tables 1 to 3.

<Test method> The indicated formulation was tested in a cavity size of 100 x 35
0 x SMIN (inside mold D (l15 ~ 50°C
), each test piece was prepared by pouring the molded product into a molded product having a density of 0.7 f/cN. The physical property tests were as follows: (1) Tensile strength according to JI8-Otsu30/) (2) Tensile elongation (
(3) Hardness CO”
C, 20 6 - °C, O"C) (Asker hardness tester C type (manufactured by Kobunshi Keiki Co., Ltd.) & Koyoru).

Table 1 shows examples when the type of ester compound is changed, Table 2 shows examples when the blending ratio of the ester compound to the polyol component is changed, and Table 3 shows examples when the proportion of the ester compound to the polyol component was changed. Examples in which polymer polyols or polyester polyols are used are shown below. Note that Comparative Example 2 is an example in which the amount of crosslinking agent added was reduced. Further, in the table, f indicates the number of functional groups, MW indicates the average molecular weight, and all blended parts are parts by weight.

The results of each physical property test value in Tables 1 to 3 are shown. In addition, each test result in the table is the arithmetic mean of the middle three values measured for five test pieces.

From the results in Tables 1 to 3, it can be seen that, in terms of tensile strength, it is superior to Comparative Example 2 in which the amount of crosslinking agent is reduced, and in some cases, it is superior to Comparative Example 2 in which the amount of crosslinking agent is not reduced (Comparative Example/
・Exhibits strength that is superior to, but not inferior to, 5-6) (Example 2・
<t-S・7・za・ri・, 23.2 Otsu・27). Also,
Regarding the temperature dependence of hardness, those with a reduced amount of crosslinking agent,
Each embodiment is better than both those that do not.

Accordingly, it can be seen that even if the hardness of the urethane foam product manufactured by the method of the present invention is decreased, the decrease in mechanical strength is small and the temperature dependence of hardness is improved.

Claims (1)

[Scope of Claims] 1. A urethane characterized in that when molding a urethane foam product, seven or more ester compounds selected from the following compound groups are blended with a polyol component at a rate of S to 700 PHR. Method of manufacturing foam products. (a) Phthalate ester (b) Adipate ester (C) Trimellitic acid ester (d) Phosphate ester