JPS6239615A - Production of molded elastomer article - Google Patents

Abstract

PURPOSE:To obtain a molded elastomer article having improved weather resistance, by molding an aromatic and aliphatic specific organic polyisocyanate mixture, polyol, 1-methyl-3,5-diethyl-diaminobenzene which is a chain extender, etc., by the reaction injection molding method. CONSTITUTION:(A) A mixed polyisocyanate of 95-80wt% polyisocyanate based on 4,4'-diphenylmethane diisocyanate and 5-20wt% polyisocyanate based on hexamethylene diisocyanate is mixed with (B) a polyol and (C) 1-methyl-3,5- diethyl-diaminobenzene as a chain extender within 0.95-1.20 equivalent ratio range of the isocyanate equivalent to the total active hydrogen equivalent contained in the reaction mixture and, as necessary, a catalyst, foaming agent and surfactant are added thereto to mold the resultant mixture by the reaction injection molding method. Thereby, the aimed molded elastomer article is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing polyurethane-urea elastic moldings. More specifically, a polyurethane-urea elastomer molded with excellent properties for 11i' was prepared using a reaction injection molding method (hereinafter referred to as R
This relates to a manufacturing method (referred to as IM method).

(Prior Art) In recent years, the RIM method has been adopted for manufacturing polyurethane molded products, such as automotive parts such as handles and bumpers, and housings for various devices.

A method is known in which a polyurethane-urea elastic molded article is produced by the RIM method using an organic polyisocyanate, a polyol, and an aromatic polyamine as a shear extender as raw materials.

For example, Japanese Patent Publication No. 54-17359 describes a method for producing elastic molded products by the RIM method using highly reactive polyisocyanates, relatively high molecular weight polyhydroxy compounds, polyamines, etc. . JP-A-57-42716 describes a method for producing elastic molded products by the RI'M method using organic polyisocyanates, polyoxyalkylene polyols, catalysts, amine chain extenders, etc. . Also, JP-A-57-7
Publication No. 4325 describes an elastomeric polyurethane-polyurea polymer using organic polyisocyanates, polyols, aromatic polyamines, low-molecular diols, etc., and states that this can also be applied to the RIM method. has been done.

(Problems to be Solved by the Invention) However, in these conventional techniques, an aromatic polyisocyanate is used as the organic polyisocyanate, an aromatic polyamine is used as a chain extender, and urea is added to the polymer along with a urethane bond. Introducing bonds generally improves tensile strength, tear strength, breakage, etc. However, the resulting elastomer has a disadvantage in that it has poor weather resistance compared to when a low molecular weight diol such as ethylene glycol is used as a chain extender.

As a result of extensive research in order to improve the above-mentioned drawbacks, the present inventors have found that by using a specific blend polyisocyanate as an organic polyisocyanate, the above-mentioned drawbacks can be overcome and various physical properties can be reduced. The present invention has been completed based on the discovery that weather resistance can also be improved.

Means for Solving Problem C) The present invention comprises an organic polyisocyanate (A), a polyol (B), 1-methyl-3,5-diethyl-diaminobenzene as a chain extender, and optionally a catalyst, foaming agent,
In a method for producing a polyurethane-urea bullet Pi-shaped article by reaction injection molding of a reaction mixture containing a surfactant, the organic polyisocyanate particles are 95 to 80 M of a polyisocyanate based on 4-4'-diphenylmethane diisocyanate. and polyisoisophor 85-20 based on hexamethylene diisocyanate.
Polyurethane-urea elastomeric (*formed Provide a method for manufacturing products.

In the present invention, a polyisocyanate based on an organic polyisocyanate (4,4'-diphenylmethane diisocyanate C used as Al, hereinafter referred to as 4,4'-MDI): well-known to those skilled in the art. be. For example, preforms with isocyanate groups at the terminals obtained from 4.4' MDI and low molecular weight glycols such as dipropylene glycol (hereinafter referred to as DPG), tripropylene glycol 1 or less (hereinafter referred to as TPG), or polyether diols. polymers, carbodiimide-modified 4,4'-MDI (4,4'-MDI derivatives containing carbodiimide groups), polymeric diphenylmethane diisocyanate, and mixtures thereof.

In the present invention, hexamethylene diisocyanate (hereinafter referred to as HDI) used as organic polyisocyanate (N)
Polyisocyanates based on
It is an HDI derivative treated so that the HDI content is 1.0 or less. That is, adducts and prepolymers of HDr and 18 active hydrogen-containing low-molecular compounds,
These include prepolymers of HDI and polyether polyols. The active hydrogen-containing low-molecular compound described in ivJ is water and low-molecular glycols such as ethylene glycol (hereinafter referred to as EG), DPG, and butylene glycol (hereinafter referred to as BG). Preferably, it is trimerized MDI obtained by trimerizing MDI. All of these reduce the free HDI content to 1
．． If necessary, post-treatment such as extraction or distillation is added in order to reduce the amount to less than 0 isocarbons.

Organic polyisocyanate fA used in the present invention
) is prepared by mixing 95-80% by weight of the 4,4'-MDI-based polyisocyanate and 85-20% by weight of the HDI-based polyisoisophor.

When the amount of polyisocyanate used as the HDIi base increases by 20 weight or more, the mechanical properties of the obtained polyurethane-urea elastomer deteriorate. This tendency is particularly remarkable in terms of stiffness at break and bending modulus (see Tables 2 and 5).
On the other hand, when the amount of HDI-based polyisocyanate is less than 5-fold isocyanate, the addition effect of HDI-based ApoIJ isocyanate is no longer observed (Chapter 2.3).
, and see Table 4).

When a polyisocyanate based on HD I is added in an amount of 5 to 20% by weight in an organic polyisocyanate (A),
It can be expected that the gelation time (so-called ejectable time) will be longer. Therefore, it is expected that large molded products can be produced even if a machine with a small discharge capacity is used.

Examples of the polyol (B) that can be used in the present invention include polyether polyol, polyester polyol, polybutadiene polyol, polycarbonate
topolyol, etc. Two or more of these polyols can also be used in combination.

Examples of polyether polyols include EG, diethylene glycol (hereinafter referred to as DEC), triethylene glycol (hereinafter referred to as TEG), trimethylolpropane (hereinafter referred to as TMP), glycerin, nlubitol,
One or more monomers such as ethylene oxide, propylene oxide, epichlorohydrin, etc. using as an initiator one or more compounds having at least two active hydrogen atoms such as sucrose, bisphenol A, water, ethylenediamine, tolylene diamine, diaminodiphenylmethane, etc. It is obtained by addition polymerization of one or more species by known methods. Polyester polyols include, for example, EG, DE
G, TgG, 1゜2-propylene glycol, 1.3-
B.G.

1. One or more compounds having at least two or more hydroxyl groups such as 4-BG, hexamethylene glycol, glycerin, TMP, pentaerythritol, sorbitol, etc., and malonic acid, maleic acid, succinic acid. It can be produced by a known method using one or more compounds having at least two carboxyl groups, such as adipic acid, tartaric acid, sebacic acid, terephthalic acid, etc. Also included are polyester polyols such as those obtained by ring-opening polymerization of father turnips.

The chain extender 1-methyl-3,5-diethyl-diaminobenzene is 1-methyl-3,5-diethyl-2,4
-diaminobenzene, 1-methyl-3,5-diethyl-
2,6-diaminobenzene or a mixture thereof. The amount used is 5 to 5 based on polyol (B).
0% by weight, preferably 8-40% by weight.

As catalysts that can be used as required, all catalysts used in the production of polyurethane can be used. For example, tertiary amines such as triethylamine, monoethanolamine, jetanolamine, triethanolamine, triethylenediamine, tetramethylpropanediamine, tetramethylhexamethylenediamine, dimethylcyclohexylamine, and dibutyltin dilaurate (hereinafter referred to as DBTDL) , dibutyltin diacetate, stannath octoate, and other organometallic compounds.

The amount of these catalysts to be used is 0.001 to 5 parts by weight, preferably 0.05 to 2 parts by weight, based on the polyol (B).

Further, blowing agents can be broadly classified into inert low boiling point solvents, reactive blowing agents, and the like. As the inert low-boiling solvent, salt fluorinated alkanes are generally used, and specific examples include methylene chloride, methylene trichloride, trichlorofluoromethane, dichlorodifluoromethane, dichloromonofluoromethane, dichlorotetrafluoroethane, and dibromomonofluoromethane. Examples include methane. Reactive blowing agents include water.

Furthermore, examples of the surfactant include polyoxyalkylene-based surfactants such as polyoxyalkylene alkyl ether and polyoxyalkylene alkylaminoether, and silicone-based surfactants such as organopolysiloxane and siloxane oxyalkylene copolymer.

In carrying out the present invention, colorants, reinforcing materials, fillers, flame retardants, antioxidants, ultraviolet absorbers, and other auxiliaries and additives may be used as necessary.

The ratio of the organic polyisocyanate (A) to the polyolate B) is such that the ratio of the isocyanate equivalent in the organic polyisocyanate (N) to the total active hydrogen equivalent contained in the reaction mixture (hereinafter referred to as NGO index) is 0. A range of .95 to 1.20 is preferable. If this equivalence ratio is smaller than 0.95, the hardness of the obtained elastic body decreases. In particular, the decrease in tensile strength and tear strength is significant. If this equivalent ratio exceeds 1.20, the resulting elastic body will become hard and brittle, and its elongation at break will decrease.

(Effects of the Invention) The elastic body obtained by the present invention not only has excellent physical properties such as 5 tensile strength, tear strength, and elongation at break, but also
Weather resistance is also good.

In the present invention, in which a polyisocyanate based on HDI is used in an amount of 5 to 20 times in the organic polyisocyanate (A), it can be expected that the gelation time (so-called dischargeable time) will be longer. Therefore, it is expected that large molded products can be produced even if a machine with a small discharge capacity is used.

The elastic body obtained according to the present invention can be used for automobile parts such as steering wheels, bumpers, headrests, instrument panels, etc., housings of various equipment, soles of shoes, etc.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

The following materials were used in the practical row.

1: Polyol premix A 90 parts by weight of polyether polyol (FA-909 manufactured by Sanyo Chemical Industries, Ltd.), 10 parts by weight of black toner (N[L7 manufactured by Toyo Ink Co., Ltd.), DETDA (1-methyl-
80:20 mixture of 3,5-diethyl-2,4-diaminobenzene and 1-methyl-3,5-diethyl-2,6-diaminobenzene (manufactured by Ethyl Corporation), 24 parts by weight, and D B
A polyol premix A'f was prepared by mixing 0.1 part by weight of TDL.

■I: Organic polyisocyanate 1 Coronate 1057 4.4'MDI base prepolymer, NCO content 26.5% (manufactured by Japan Polyurethane Industries Co., Ltd.) 2. Coronate EH Trimer type polyisocyanate of hexamethylene diisocyanate, NCO content 21°0 In charge, free HDI0
．． 9 or less (manufactured by Nippon Zero Urethane Kogyo Co., Ltd.) 3. Coronate 2094 Hexamethylene diisocyanate base prepolymer N
GO content 16.1%, free HD 11.0% or less (manufactured by Nippon Polyurethane Industries Co., Ltd.) Example 1 Coronet 1-1057 and Coronet)-EH 951
Mixed in weight ratios of 5.90/10 and 85/15, with an NGO index of 95.10 in each case.
Three amounts of polyol premix A, 5 and 115, and a high pressure foam injection machine (MG 120/120,
(Niigata Tekko Shinsei) and injection molded into a mold under the molding conditions shown in Table 1.

The physical properties and weather resistance of the obtained molded article were investigated. The results are shown in Table 2.

(Note) (1) Hardness Shore D is ASK manufactured by Kobunshi Keiki Co., Ltd.
Shore D (ASTM2240-75
).

(2) Tensile strength, tear strength, bending modulus, and breaking strength were in accordance with JIS K-6301.

(3) For heat-resistant JE, the molded product is coated with polyester urethane-based Planit S (white) manufactured by Dainippon Toyo Co., Ltd., and this coated product is coated with the Weather-O-Meter WEL-8U- manufactured by Ska Test Instruments Co., Ltd. After being exposed to NHC type [light source: sunshine arc (carbon)] at 80°C for 4400 hours, it was measured using a color difference meter (manufactured by Suga Test Instruments Co., Ltd.) as a standard for all unexposed products.

(4) Weather resistance ΔE was determined by conducting a test under the same conditions and operations as for heat resistance except for 400 hours at 63°C.

Example 2 Coronate EH in Example 1 was replaced with Coronate 2094, and all songs were changed in the same manner as in Example 1. Physical properties and weather resistance of the obtained molded product were investigated. The results are shown in Table 3. The measurement conditions were the same as in Example 1.

Ratio V Example 1 The physical properties and weather resistance of a molded article obtained in the same manner as in Example 1 except that Coronate 1057 was used as the organic polyisocyanate were investigated. The results are shown in Table 4. The measurement conditions were the same as in Example 1.

Table 4 Comparison of Examples 1 and 2 with Comparative Example 1 shows that by using a mixed polyisocyanate, heat resistance and weather resistance can be improved without deteriorating various physical properties.

Comparative Example 2 The weight ratio of Coronate 1057 and Coronate EH was 7
The physical properties and 11 weather properties of the molded product obtained in exactly the same manner as in Example 1 except that the molded product was changed to 5/25 were investigated. The results are shown in Table 5. The measurement conditions were the same as in Example 1.

Table 5 Comparison of Example 1 and Comparison Row 2 shows that the usage ratio of polyisocyanate based on polyisocyanate based on hexamethylene diisocyanate exceeds 20% by weight based on the total organic polyisocyanate 1'-1=(・It can be seen that the physical properties, especially the shear elongation and +11 + modulus, decrease.

Applicant: Inoue MCHIP Stock Accounting Japan Polyurethane Industries Co., Ltd. Yoshitsune Inoue/Paka Akira Fujioki 1T “” ;-ri・]co

Claims (1)

[Claims] 1. Organic polyisocyanate (A), polyol (B)
, a reaction mixture containing 1-methyl-3,5-diethyl-diaminobenzene as a chain extender, and optionally a catalyst, a blowing agent, and a surfactant, by a reaction injection molding method to form a polyurethane-urea elastomer. In the method for producing a product, the organic polyisocyanate (A) is composed of 95 to 80% by weight of a polyisocyanate based on 4-4'-diphenylmethane diisocyanate and 5 to 20% by weight of a polyisocyanate based on hexamethylene diisocyanate. A method for producing a polyurethane-urea elastomer molded article, which is a mixed polyisocyanate, and the ratio of the isocyanate equivalent to the total active hydrogen equivalent contained in the reaction mixture is in the range of 0.95 to 1.20. 2. Prepolymers in which the polyisocyanate based on 4,4'-diphenylmethane diisocyanate has a terminal isocyanate group obtained from 4,4'-diphenylmethane diisocyanate and low molecular weight glycols or polyether diols; The method according to claim 1, characterized in that the method is selected from the group consisting of 4,4'-diphenylmethane diisocyanate derivatives containing carbodiimide groups and terminal isocyanate groups; polymeric diphenylmethane diisocyanates; and mixtures thereof. . 3. The hexamethylene diisocyanate-based polyisocyanate is selected from the group consisting of prepolymers of hexamethylene diisocyanate and low molecular weight glycols or polyether diols, trimerized hexamethylene diisocyanate, and mixtures thereof; The method according to claim 1, wherein the free hexamethylene diisocyanate content is 1.0% by weight or less. 4. A patent claim characterized in that the polyisocyanate based on hexamethylene diisocyanate is a hexamethylene diisocyanate trimer having terminal isocyanate groups and having a free hexamethylene diisocyanate content of 1% by weight or less The method described in item 1 of the scope. 5. The method according to claim 1, wherein the polyol (B) is selected from the group consisting of polyether polyols, polyester polyols, polybutadiene polyols, polycarbonate polyols, and mixtures thereof. 6. The method according to claim 2, wherein the low molecular weight glycol is dipropylene glycol or tripropylene glycol. 7. The method according to claim 3, wherein the low molecular weight glycol is ethylene glycol, dipropylene glycol or butylene glycol.