JPH01311116A - Production of polyurea-based elastic elastomer - Google Patents

Abstract

PURPOSE:To improve the flowability of liquid into a mold, brittle fracture in demolding, etc., in the production of the subject product by reaction injection molding process, by using a specific aromatic diamine as at least a part of primary aromatic diamine used as a chain extender. CONSTITUTION:The objective product can be produced by the reaction injection molding of (A) a polyisocyanate, (B) a compound containing active hydrogen and having high molecular weight, (C) a primary aromatic amine containing an aromatic diamine (e.g., N'-ethyl-2,4-diaminotoluene) having an amino group converted to secondary state with 1-10C alkyl or 7-15C aralkyl and (D) other assistants. A preferable example of the component A is a polyisocyanate containing urethane group and produced by reacting 4,4'-diphenylmethane diisocyanate with a low-molecular weight diol.

Description

Detailed Description of the Invention [Industrial Field of Application] Relatively high-density polyurethane and polyurea elastic elastomer molded products produced by reaction injection molding have excellent physical properties, moldability, and appearance, and are used in a wide range of fields. used in

Specific examples of applications include a wide range of applications, such as automobile plate materials, sports and leisure goods, office equipment housings, furniture, and agricultural equipment.

The most commonly used of these are automobile bumpers, fascias, fenders, doors, side moldings and the like.

[Conventional technology]

By polyaddition of isocyanate and active hydrogen-containing compound, non-foaming polyurethane (including polyurea, the same shall apply hereinafter) is produced.
It is known to mold fiber-reinforced elastomers, microcellular polyurethane elastomers, or microcellular polyurethane elastomers by reaction injection molding.

The raw materials for these polyurethanes or polyureas are polyisonanate, high molecular weight active hydrogen-containing compounds (polyether polyols, polyester polyols, polyether polyamines, etc.), and low molecular weight active hydrogen-containing compounds (alkanediols, aromatic polyamines, etc.) , and, if necessary, a catalyst, a blowing agent, an additive, and a fibrous inorganic compound.

Reaction injection molding method
n Molding, hereinafter referred to as RI? (abbreviated as I) is a method in which an isocyanate and an active hydrogen-containing compound are impact-mixed under pressure (often under high pressure) using an injection molding machine, the mixture is filled into a mold, and the molded product is removed after curing. .

A detailed description of the reaction injection molding method can be found, for example, in the following document: "Reaction Injection Mold"
driving in the auto-motive
Industry'', Journal of Ce1
1. Plastics.

Vol. 2.1975; “Plastics for Auto-mobile
e 5afety Bumpers”.

Journal of Ce11. PIastics
, Vol 2+ 1973 Among the above raw materials, chain extenders are particularly important because they have a large effect on moldability and physical properties.

[Problems to be Solved by the Invention] As chain extenders, low-molecular-weight alkanediols or certain aromatic polyamines are used for boat fishing, but they do not always have sufficient performance in terms of molding or physical properties. It is not something that is given.

Specifically, when ethylene glycol is used, cell roughness, loose skin, pinholes, sink marks, and residual molding tend to occur, and when carried out industrially, productivity is extremely low and unsatisfactory.

The above methods have poor physical properties such as curing properties and heat resistance, so
One way to improve this is to use ethylene glycol and aromatic polyamine in combination.

For example, JP-A-52-77200 describes a method for improving curing properties and heat resistance by using ethylene glycol and a polynuclear mixed aromatic polyamine synthesized by condensation of aniline and formalin. ing.

However, with this method, the flowability of the mixed liquid within the mold is reduced, and the drawbacks of the above method, such as cell roughness, pinholes, and sink marks, are not sufficiently improved.

Although the above methods have various drawbacks, they are still used in domestic production sites.

As another method, for example, in JP-A-56-109216, an aliphatic amine is used in combination with ethylene glycol to improve mechanical strength and heat resistance. However, since this method mainly uses ethylene glycol as a chain extender, significant improvements in mechanical strength and heat resistance cannot be achieved.

The present inventors have confirmed that aliphatic amines with relatively large molecular weights, which are most frequently used as "preferred" examples in the patent, do not themselves significantly improve curing properties and heat resistance. .

On the other hand, as a method of using an aromatic primary amine as the main chain extender, for example, as described in Japanese Patent Publication No. 54-17359, there is The hydrogen in the carbon number 1-3
There is a method of substituting with a straight-chain alkyl group to reduce the reactivity of the amino group due to steric hindrance, thereby improving liquid flow into the mold.

The method using this type of aromatic primary diamine requires a shorter demolding time than ethylene glycol or 1,4-butanediol.
Currently, in the United States, diethyltoluenediamine (DETDA), which is shown in the example of the patent, is used in most products such as bumpers and fascia because it has a fast curing time and excellent heat resistance and tensile properties. ing.

However, in this method, the activity of the aromatic primary diamine is still too high, so a large molding machine is essential and the equipment investment is very large.

In addition, when manufacturing large molded products with complex shapes or thin-walled molded products, it is not possible to obtain good molded products.Furthermore, if a large amount of DETDA is used, it becomes brittle during demolding. There are manufacturing problems such as easy breakage and sink marks.

Further, as another method, for example, JP-A-58-32626
As disclosed in Japanese Patent Publication No. 1, there is a method in which diaminohenzene containing 10-gene, which has low reactivity, is used as a chain extender.

In this method, the reactivity of halogen-containing diaminobenzene is moderately fast, but curing is too slow and molding is impossible.

[Means to solve the problem]

As a result of intensive research on aromatic primary diamine compounds, the present inventors discovered that
By replacing part or all of the class diamine with "an aromatic diamine in which one of the amino groups is secondaryized with an alkyl group or an aralkyl group," liquid flowability and flexibility during demolding can be improved. They discovered this and arrived at the present invention.

That is, the present invention provides polyisocyanate, a high molecular weight active hydrogen-containing compound,
In a method for producing an elastic polyurea elastomer molded product from an aromatic primary diamine and other auxiliary agents by reaction injection molding, one of the amino groups of the aromatic primary diamine is changed to 2 by a 1-10 alkyl group or a C7-15 aralkyl group
The present invention relates to a method for producing a polyurea-based elastic elastomer molded article, characterized in that a graded aromatic diamine is used in part or in whole.

In the above invention, the alkyl group having 1 to 10 carbon atoms is suitably an ethyl group, isopropyl or tert-butyl group, and the aralkyl group having 7 to 15 carbon atoms is suitably a benzyl group or a phenethyl group.

Examples of aromatic diamines in which one of the amino groups is secondaryized with an alkyl group having 1 to 10 carbon atoms or an aralkyl group having 7 to 15 carbon atoms to be used in the present invention include, for example, l-nuclear system primary diamines: No-ethyl-2,4-diaminotoluene N-ethyl-
2,4-diaminotoluene No-isopropyl-2,4
-Diaminotoluene N-isopropyl-2,4-diaminotoluene N'-tert-butyl-2,4-cyaminotoluene N-9-chary-butyl-2,4-diaminotoluene N''-ethyl-2,6- Cyamitsutoluene N-ethyl-
2,6-diaminotoluene N-isopropyl-2,6-
Diaminotoluene N-isopropyl-2,6-diamittoluene N'-tert-butyl-2,6-cyaminotoluene N-tert-butyl-2,6-diaminotoluene N-isopropyl-paraphenylenediamine N-tert. Butyl-paraphenylenediamine N-Isopropyl-Meta-phenylenediamine N-T-Butyl-Meta-phenylenediamine No-Ethyl-5-tert-butyl-2,4-diaminotoluene N-Ethyl-5-tert-butyl-2,4 -Diaminotoluene N"-isopropyl-5-tert-butyl-2,4
-Diaminotoluene N-isopropyl-5-tert-butyl = 2.4-
Diaminotoluene No-tert-butyl-5-tert-butyl-
2,4-diaminotoluene N-tert-butyl-5-tert-butyl-2
, 4-Diaminotoluene No-ethyl-3-tert-butyl-2,6-diaminotoluene N-ethyl-3-tert-butyl-2,6-diaminotoluene No-isopropyl-3-tert-butyl-2,6
-Diaminotoluene N-isopropyl-3-tert-butyl-2゜6-
Diaminotoluene No-tert-butyl-3-tert-butyl-
2,6-diaminotoluene N-tert-butyl-3-tert-butyl-2
,6-diaminotoluene No-benzyl-2,4-diaminotoluene N-benzyl-2,4-diaminotoluene N-phenethyl-2,4
-Diaminotoluene N-Phenethyl-2,4-diaminotoluene No-Benzyl-2,6-siamittoluene N
-benzyl-2,6-diamitluene, N-phenethyl-2,6-diamitluene N-phenethyl-2,
Examples include 6-cyamitoluene N-benzyl-paraphenylenediamine N-benzyl-metaphenylenediamine.

Further, as the dinuclear primary diamine, for example, N-ethyl-4,4'-diaminodiphenylmethane N-isopropyl-4,4°-diaminodiphenylmethane N-tert-butyl-4,4'-diaminodiphenylmethane N- Ethyl-4,4°-diaminodiphenylethane N-isopropyl-4,4°-diaminodiphenylethane N-couchary-butyl-4,4°-diaminodiphenylethane N-benzyl-4,4°-diaminodiphenylmethane No, - Benzyl-4,4°-diaminodiphenylmethane N-ethyl-4,4°-diaminodiphenyl ether N-isopropyl-4,4°-diaminodiphenyl ether N-tert-butyl-4,4°-diaminodiphenyl ether N-ethyl-3, Examples include 4''-diaminodiphenyl ether, N-isopropyl-3,4''-diaminodiphenyl ether, N-tert-butyl-3,4''-diaminodiphenyl ether, and the like.

Aromatic diamines in which one of the primary amino groups as described above is secondaryized with an alkyl group or an aralkyl group are, for example,
An aromatic primary diamine and an alkyl halide having 1 to 10 carbon atoms (e.g., ethyl chloride, isopropyl chloride, tertiary-butyl bromide, etc.) or an aralkyl halide having 7 to 15 carbon atoms (e.g., benzyl chloride, phenethyl bromide, etc.) It can be synthesized by reacting without a catalyst in a suitable solvent such as dioxane at a temperature of 50 to 120°C, followed by neutralization with an alkali.

At this time, the aromatic diamine in which two of the primary amino groups produced as a side reaction are secondaryized has a very m! It is.

Generally, aromatic primary diamines have a relatively high melting point and are often difficult to dissolve in high molecular weight active hydrogen compounds such as polyether polyols and polyether polyamines.

On the other hand, the above-mentioned "aromatic diamines in which only one of the primary amino groups is secondaryized with an alkyl group or an aralkyl group" are mostly liquid or have a low melting point, and are similar to polyether polyols and polyesters. Soluble in high molecular weight active hydrogen compounds such as ether polyamines.

Therefore, by replacing part or all of the aromatic primary diamine with these "aromatic diamines in which only one of the primary amino groups is secondaryized with an alkyl group or an aralkyl group", solubility is improved. .

In addition, all aromatic primary diamines are highly reactive, so
During reaction injection molding, the liquid flowability of the reaction mixture inside the mold is very poor, but if the above-mentioned "aromatic diamine in which only one of the primary amino groups is secondaryized with an alkyl group or an aralkyl group" is used, , the amount of aromatic primary diamine used can be reduced, and liquid flowability can be improved without significant deterioration of physical properties.

Examples of the aromatic primary diamine used in the present invention include 2,4-diaminotoluene, 2,6-cyaminotoluene, paraphenylenediamine, metaphenylenediamine, 3,5-diethyl-2,4-diaminotoluene, and 3.5-diaminotoluene.
Diethyl-2,6-diamittoluene 3-isopropyl-2,6-diamittoluene 5-isopropyl-2,4
-diaminotoluene 5-tert-butyl-2,4-
Diaminotoluene 4.4'-methylene-bis-(2,6-ethylaniline) 4.4'-methylene-bis-(2,6-diitubrobylaniline) 4.4'-methylene-bis-( 2-ethylaniline) 3.4°-diaminodiphenyl-1,1°-ethane 5.7-diami2-1,1-dimethylindane 4.6-
Jiami Two 1. 1-dimethylindane 4.7-diami2 1,1-dimethylindane 5.7-diami2 1. l
, 4,6-titramethylindane, and the like.

Examples of the polyisocyanate used in the present invention include 4.4°-diphenylmethane diisocyanate, 2.
4- and/or 2.6-1 lylene diisocyanate,
Polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, isophorone diisocyanate,
These include other aliphatic polyisocyanates and dimers, 31-mers, carbodiimide-modified products, allophanate-modified products, Biuret-modified products, prepolymers, etc. of these isocyanates.

A particularly preferred isocyanate compound is a modified form of 4,4°-diphenylmethane diisocyanate, which is liquid at room temperature. Specific examples of this compound include: 4,4
' - Urethane group-containing polyisocyanate obtained by reacting diphenylmethane diisocyanate with a low molecular weight diol or triol (preferably polypropylene glycol having a molecular weight of less than 700), or a 4,4°- containing carbodiimide group and/or uretonimine group. Diphenylmethane diisocyanate-based polyisocyanate. Examples of preferred polyisocyanates include; products obtained by modifying a mixture of 2,4°- and 4.4°-diphenylmethane diisocyanates as described above, or 4,4°-modified as described above; It is a mixture of diphenylmethane diisocyanate and a small amount of diphenylmethane-based polyisocyanate having a higher functionality than difunctionality.

The high molecular weight active hydrogen-containing compound used in the present invention is an active hydrogen compound having a practical molecular weight of 1,000 to 18,000, and specifically includes the following compounds. As an initiator, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol,
Polyether polyols obtained by addition polymerizing alkylene oxide to polyhydric alcohols such as dipropylene glycol, glycerin, trimethylolpropane, 1,3,6-hexanetriol, pentaerythritol, and sorbitol; also jetanolamine, triethanol Alkanolamines such as amines, ethylenediamine,
Polyether obtained by addition polymerizing ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. to amines containing two or more active hydrogens such as diethylenetriamine, ammonia, aniline, tolylene diamine, xylylene diamine, and diaminodiphenylmethane. Polyols include polytetramethylene ether glycol obtained by ring-opening polymerization of tetrahydrofuran.

In addition, a polymer polyol obtained by grafting an ethylenically unsaturated compound such as styrene, acrylonitrile, or methyl methacrylate to the above polyol, and 1,
2- or 1,4-polybutadiene polyols or hydrogenated products thereof can also be used.

Furthermore, polyester polyols obtained by reacting polycarboxylic acids with low molecular weight polyols, polyester polyols obtained by ring-opening polymerization of caprolactone, and polycarbonate polyols can also be used.

In addition to the above high molecular weight active hydrogen-containing compounds, for example,
A primary or secondary amine obtained by aminating the OH group of the above polyether polyol, specifically a polyether polyol obtained by addition polymerizing propylene oxide to glycerin, in the presence of a catalyst with ammonia or an alkyl amine. There are high molecular weight polyether polyamines obtained by the reaction. Alternatively, it may be a polyether polyamine obtained by hydrolyzing a prepolymer obtained by reacting a polyether polyol and an isocyanate, or a polyether polyamine obtained by chemically bonding a high molecular weight polyether and an aromatic amine. It may be.

When carrying out the present invention, the equivalent ratio of NGO groups and active hydrogen-containing compounds contained in the polyisocyanate is from 0.8 to
Adjust the amount of each raw material used so that it becomes 1.3.

In addition to the above raw materials, auxiliary agents include catalysts, blowing agents, internal mold release agents, fillers, pigments, antioxidants, weathering stabilizers, and the like.

Examples of catalysts include organometallic catalysts such as dibutyltin diacetate, diptyltin dilaurate, silver oleate, and octane, and triethyleneamine and N.

N, N', N'-tetramethylpropanediamine,
1.4-diazabicyclo-(2,2,2)-octane,
An amine catalyst such as pentamethyldiethylenetriamine.

As a blowing agent, for example, trichlorofluoromethane, C
CI□F-CCIF, notylene chloride, water, nitrogen gas, carbon dioxide gas, etc.

As the internal mold release agent, a silicone type or the like is used.

Fillers include glass fiber, flake glass, mica,
Talc, inorganic compound whiskers, etc. are used.

[Effect]

In the present invention, a part of the conventionally known fast-reacting aromatic primary diamine is replaced with an aromatic diamine in which one of the primary amino groups is secondaryized with an alkyl group or an aralkyl group. Flowability and brittleness during demolding are improved.

[Example] A mixed solution was prepared using the raw material #4 below, and RIM molding was performed in a mold using an injection molding machine for polyurethane.

Zu J ≧ Nino Nishi J5: A polyoxyalkylene triol having a hydroxyl value of 28 mg KOII/g and a primary hydroxyl group content of 75% obtained by addition polymerizing propylene oxide and ethylene oxide to glycerin.

Mizujokaji + Dan: Triol with a molecular weight of about 5000 obtained by addition polymerizing propylene oxide to glycerin,
80 obtained by reaction with isopropylamine in the presence of a catalyst
% secondaryized polyether triamine.

Isocyanate A: 4.4°-Diphenylmethane diisocyanate and tripropylene glycol are reacted to form an NCO group-containing N26° 0% isocyanate prepolymer.

DETDA: rDETDA from Lonza, 3°5-
A mixture of diethyl-2,4-diaminotoluene and 3°5-diethyl-2,6-diaminotoluene in a weight ratio of 80,720.

m-TDA: 2.4 with 'm-TDAJ manufactured by Mitsui Toatsu Chemical ■
- A mixture of diaminotoluene and 2,6-diaminotoluene in a weight ratio of 80:20.

-; To: N-benzyl-2,4 (or 2.6)-diaminotoluene and N-benzyl- obtained by reacting rm-TDAJ with benzyl chloride in a dioxane solvent. A mixture of 2,4 (or 2,6)-diaminotoluenes.

N'-tert-butyl-2,4 (or 2,6)- obtained by reacting rm-TDAJ with tert-butyl chloride in dioxane solvent
Diaminotoluene and N-tert-butyl-2,4(
or 2.6) -A mixture of diaminotoluenes.

DBTDL: Tin catalyst for urethane manufactured by Nitto Kasei.

Dibutyltin dilaurate.

B-712: Wax-based external mold release agent for urethane RIM manufactured by Middle East Yushi ■.

Examples 1 to 6 and Comparative Examples 1 to 3 Molding was performed using the raw material formulations listed in Table 1 as Examples and Table 2 as Comparative Examples.

The reaction injection molding machine used was NR-230 manufactured by Toho Kikai Co., Ltd. Adjust the temperature of the resin and isocyanate to 40°, adjust the blending ratio to the above amount, and injection speed 3.
It was injected into the mold at 30 g/sec.

A sheet mold measuring 500 mm x 4005 m x 2.5 lm was used as the mold, and after heating to 75°C, an external mold release agent was applied and the mold was thoroughly wiped with a dry cloth.

The mold was removed 30 seconds after injection, and the releasability and curing properties were compared. Cure performance was determined by placing the sheet molded product on a horizontal table immediately after demolding, and measuring the height of the drop from the horizontal surface by protruding 20 cm from the tip of the sheet after 1 minute, and determining the quality of the cure performance based on its size. . At the same time, in order to see how brittle the sheets were immediately after being formed, the sheets were bent to see if they would crack.

The surface condition of the molded product was also examined. Furthermore, the value obtained by dividing the filling distance (C1l) to the tip of the sheet by the total sheet weight (g) was defined as the "liquid flow index (c + s/g) J" to examine the liquid flow properties.The liquid flow index is the value The larger the value, the better the liquid flow.

Physical properties were determined by cutting a test piece from the molded product, heating it in an oven at 120°C for 1 hour, and then measuring tensile strength, elongation, bending modulus, and heat resistance. Heat resistance test is 2 cm
A 15cm strip-shaped test piece was fixed horizontally at a position 5c+a from one end, and placed in a thermostat at 120°C for 1 hour.
After standing for a period of time, the vertical path N (heat sag) when the other end sagged was measured, and the heat resistance was compared.

The results are shown in Tables 1 and 2.

In Examples 1 to 3, when a secondary amine A or B was used in addition to the fast-reacting aromatic primary diamine (m-TDA, DETDA) as a chain extender diamine, the liquid elongation properties were good. Ta.

On the other hand, as shown in Comparative Example 1.2, a fast-reacting aromatic primary diamine (m-TDAS) was used as a chain extender diamine.
When DETDA) was used alone, the liquid elongation properties were poor.

In Example 4, instead of polyether A, the fast-reacting 1
When the grade amine-terminated polyether was used, although the liquid elongation was naturally lower than that of polyether A, overall satisfactory moldability and physical properties were obtained. In other words, in Examples 5 and 6, which had sufficient performance even with polyurea systems that used only amine compounds as raw materials, when the amount of chain extender diamine used in Examples 1 to 3 was increased, normal No fragility during demolding, which is often seen, was observed.

On the other hand, as shown in Comparative Example 3, when a fast-reacting aromatic primary diamine was used alone as a chain extender diamine and the amount used was increased, the product became brittle and cracked during demolding.

〔Effect of the invention〕

As is clear from Examples 1 to 6, the method of the present invention was found to have superior molding performance to the conventional technique during injection molding of polyurethane.

Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Scope of Claims] 1. A method for producing a polyurea-based elastic elastomer molded product from a polyisocyanate, a high molecular weight active hydrogen-containing compound, an aromatic primary diamine and other auxiliaries by a reaction injection molding method, As a primary diamine,
One of the amino groups of the aromatic primary diamine has 1 to 1 carbon atoms.
1. A method for producing a polyurea-based elastic elastomer molded article, characterized in that part or all of an aromatic diamine secondaryized by an alkyl group of 0 or an aralkyl group of 7 to 15 carbon atoms is used. 2. The method for producing an elastic polyurea elastomer molded article according to claim 1, wherein the alkyl group having 1 to 10 carbon atoms is an ethyl group, isopropyl or tertiary butyl group. 3. The method for producing an elastic polyurea elastomer molded article according to claim 1, wherein the aralkyl group having 7 to 15 carbon atoms is a benzyl group or a phenethyl group.