JPH02269725A - Production of polyurethane urea and its molding - Google Patents

Abstract

PURPOSE:To obtain an elastic molding having a dense skin by reaction-injection- molding a mixture of a polyisocyanate, a high-MW polyether polyol, a specified aromatic diamine, a fatty acid salt of Bi, and an organic acid. CONSTITUTION:A polyurethane urea molding is obtained by reaction-injection- molding a mixture of a polyisocyanate, a polyether polyol of an MW of 1000-18000, an aromatic diamine selected from among 2,4-diamino-5-tert- butyltoluene, 2,6-diamino-3-tert-butyltoluene, 3,4-diamino-5-tert-butyltoluene and 2,3-diamino-4-tert-butyltoluene, a fatty acid salt of Bi, and an organic acid in a sealed mold. As the polyisocyanate, a 4,4'-diphenylmethane diisocyanate derivative which is liquid at room temperature is particularly desirable.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a polyurethane urea elastomer produced by reaction injection molding technology, and more specifically, it relates to a polyurethane urea elastomer produced by reaction injection molding technology, and more specifically, it relates to a polyurethane urea elastomer made of a highly reactive polyisocyanate, a high molecular weight polyether polyol, and an aromatic amine chain. The present invention relates to a method for producing an elastic molded article having a dense skin by reaction injection molding technology using an extender, and the elastic molded article obtained thereby.

(Prior Art) Polyurethane elastic molded products having a dense surface and excellent physical properties, moldability, and appearance are widely used. Specific examples of applications include automobile boards, sports and leisure goods, office equipment housings, furniture, agricultural equipment, etc. The most commonly used of these are automobile bumpers, fascias, doors, side moldings and the like.

Isocyanate compounds and isocyanate-reactive compounds (
It is known to mold non-foamed polyurethanes, fiber-reinforced elastomers or microcellular polyurethane elastomers by reaction injection molding by polyaddition with active hydrogen compounds). The raw materials for these polyurethanes are usually
The 6-reaction injection molding process, which includes polyisocyanates, polyether polyols and polyester polyols having hydroxyl groups, chain extenders and catalysts, as well as appropriately used blowing agents, auxiliaries, additives and fibrous inorganic compounds, is
action injection molding
(hereinafter referred to as RIM), the incyanate compound and the incyanate-reactive component mixture are impingement-mixed under pressure (often under high pressure) using a mixing injection machine, and this mixture is filled into a mold, hardened, and then molded. This is a method for taking out items. A detailed description of RIM can be found in the following literature, for example: [Reaction Injection Molding in the Automotive Industry” Journal of Cell Plastics Vol. 1.2.1975
Year (“Reaction Injection Mold
ing in the Auto-motiveInd
ustry, Journal of Ce11.
Plastic, Vol. 2゜1975:
) Plastics for Automobile Safety Bumper J Journal・Sabu・Cell・Plastics Vol. 1.2゜1973 Plastics for Auto-Mobile
e Safety Bumpers, Journa
l of Ce11. Plastic, Vol.
2゜1973).

Among the raw materials used above, chain extenders and catalysts have a particularly large (important) effect on moldability and physical properties. Conventionally, chain extenders have generally been ethylene glycol, and recently diethyltoluenediamine (hereinafter referred to as DETDA) has been used as a chain extender. In addition, as a catalyst, a combination catalyst of a tin catalyst such as dibutyltin dilaurate and an amine catalyst such as triethylenediamine is usually used. R using DETDA as the agent and a combination catalyst of dibutyltin dilaurate and triethylene diamine as the catalyst.
IM urethane urea composition (hereinafter referred to as DETDA method)
is disclosed.

This method produces a urethane urea elastomer that has a quick demolding time (curing time) and excellent heat resistance and tensile properties.Currently, it is used in most products such as bumpers and fascias in the United States. The disadvantage of this method is that the activity is still too high, so it is necessary to use a large molding machine, which requires a very large investment in equipment.Also, because the discharge time is short, it is difficult to use large molded products, molded products with complex shapes, or thick walls. When producing a thin molded article, there is a problem that it is not possible to obtain a molded article with a good appearance.As a method for improving this method, for example, the following documents and patents are available.

"Structure-Property Relationship of Chain Extenders: Highly Processable Aromatic Diamines for RIM" Polyurethane Technology/Marketing 30th Annual Conference, October 15-17, 1986 (
”Chain Extender 5structure
-Physical Property Re1ati
onships: HlghlyProcessab
le Aromatic Diaa+ine For
RIM” 30THANNUAL POLYURETH
ANE TECHNICAL/MARKETINGCO
NFERENCE, 0CTOBER15-17,19
86), JP-A No. 62-50320, this document and the published publication contain tert- as an aromatic amine.
A method for obtaining a RIM urethaneurea molded article using butyltoluene diamine (t-BTDA) and a combined catalyst of dibutyltin dilaurate and triethylene diamine (hereinafter referred to as the t-BTDA method) is disclosed.

(Problem to be solved by the invention) Compared to the DETDA method, the t-BTDA method allows demolding in less than 30 seconds despite its lower activity, and in formulations with high surface rigidity, It has the advantage of low surface rigidity and easy demolding work. However, as described in the above literature, the heat resistance (heat sagging resistance) of the product molded product is inferior to that of the DETDA method;
Therefore, for example, in automotive applications, there is a problem in that heat sag occurs when applying metallic paint. Furthermore, in the case of Oshi C, which has a low surface rigidity, the hardness upon demolding was too low and there was a problem in shape retention. In addition, we investigated reducing the activity of DETDA by changing the type, amount, and ratio of the amine catalyst and tin catalyst, which were conventionally disclosed in the DETDA method.
In either case, the initial strength only decreased and the problem was not solved.

As described above, none of the conventional methods have been satisfactory in terms of moldability and physical properties.

(Means for Solving the Problems) The present inventors have conducted extensive studies to develop a method that has short demolding time, good moldability, and excellent physical properties such as shape retention and heat resistance. In particular, it has been discovered that the purpose can be achieved by using a specific aromatic diamine as a chain extender in combination with a specific catalyst system, and the present invention has been achieved.

That is, the present invention comprises: (a) polyisocyanate (b) polyether polyol having a molecular weight of 1,000, 18,000 (c) 2,4-diamino-5-tert-butyltoluene, 2
．． Aromatic diamine (d)Bi selected from the group consisting of 6-diamino-3-tert-butyltoluene, 3,4-diamino-5-tert-butyltoluene, and 2,3-diamino-4-tert-butyltoluene and (e) an organic acid, and optionally (f) a blowing agent, an internal mold release agent, a filler, and other auxiliaries. A polyurethane characterized by reaction injection molding in a closed mold. The present invention provides a method for producing a urea molded product and the molded product obtained in this manner.

Component (C) used in the present invention, 2,4-diamino-5-tert-butyltoluene, 2,6-diamino-3-
Tert-butyltoluene, 3,4-diamino-5-tert-butyltoluene, and 2,3-diamino-4-tert-butyltoluene are compounds obtained by alkylating toluenediamine, followed by nitration and reduction. . Japanese Patent Publication No. 61-931
No. 44 discloses its manufacturing method. The preferred amount range of this diamine component (c) is 15 to 45 parts by weight per 100 parts by weight of the polyether polyol of component (b), and if the amount of this diamine component (c) is too large, the molded product will If the amount is too low, the molded product will have too low rigidity and become unsuitable for practical use.

The fatty acid salt of Bi as component (d) of the present invention is a salt of a fatty acid prepared by RCOOH, and R is an alkyl group, an aryl group, an aralyl group, or an aralkyl group having 1 to 21 carbon atoms. Methyl, ethyl, propyl, isopropyl, neopentyl, octyl, neononyl, cyclohexyl, tridecyl, neodecyl, nonadecyl,
Tolyl and naphthyl are preferred. This usage amount is the component (b)
) 0.01 to 5% by weight based on the polyether polyol
shall be.

The organic acid of component (e) of the present invention contains at least one acidic group such as a C0OH group, So, H group, or phenolic OH group.
It is a compound with a long-lasting effect. Particularly preferred are fatty acids, oxycarboxylic acids, aliphatic dicarboxylic acids, aromatic carboxylic acids, sulfonic acids, nonylphenol, and the like. For example, specific examples include 2-ethylhexanoic acid, neodecanoic acid, adipic acid,
Examples include benzoic acid, catechol, lactic acid, and F-decylbenzenesulfonic acid. The amount of this organic acid used is the component (b)
, ) is preferably 0.0 for the polyether polyol.
The amount is 1 to 5% by weight.

The polyisocyanate used as component (a) in the present invention is not particularly limited, and conventionally used polyisocyanates can be used, such as 4,4'-diphenylmethane diisocyanate, 2,4- and/or 2.4'-diphenylmethane diisocyanate. 6-
Dolylene diisocyanate, nate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate,
inphorone diisocyanate, other aliphatic polyisocyanates and dimers of these incyanates,
Examples include trimer, carbodiimide modified product, allophanate modified product, Biuret modified product, prepolymer, and the like.

Among these polyisocyanates, particularly preferred isocyanate compounds for the present invention are derivatives of 4,4'-diphenylmethane diisocyanate, which is liquid at room temperature. Specific examples of this compound include: urethane group-containing polys obtained by reacting 4,4'-diphenylmethane diisocyanate with a low molecular weight diol or triol (preferably polypropylene glycol having a molecular weight of less than 700). Polyisocyanates based on 4,4'-diphenylmethane diisocyanate having isocyanate dicarposiimide groups and/or urethane imine groups. Examples of preferred polyisocyanates also include the following: 2,4'- and 4.
A modified product prepared by modifying a mixture of 4'-diphenylmethane diisocyanate as described above: having a higher degree of functionality than the difunctionality of the 4,4'-diphenylmethane diisocyanate modified as described above and a small amount of diphenylmethane system. Mixtures with polyisocyanates, etc.

The long-chain molecular polyol used as component (b) in the present invention is also not particularly limited, and examples thereof include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,3.6- Molecular weight 1000 obtained by addition polymerizing alkylene oxide to polyhydric alcohols such as hexanetriol, pentaerythritol, sorbitol and/or these polyhydroxy compounds
There are ~1sooo polyether polyols. In addition, alkanolamines such as jetanolamine and triethanolamine, amines containing two or more active hydrogens such as ethylene diamine, diethylene triamine, ammonia, aniline, tolylene diamine, xylylene diamine, and diaminodiphenylmethane, ethylene oxide, propylene oxide, etc. , butylene oxide, styrene oxide, etc., with a molecular weight of 1000 to 18.
000 polyether polyols and polytetramethicine ether glycols can also be used.

In addition to the above, higher fatty acid ester polyols and polyester polyols obtained by reacting polycarboxylic acids with low molecular weight polyols, polyester polyols obtained by polymerizing caprolactone, polycarbonate polyols, castor oil, dehydrated castor oil, and other hydroxyl group-containing high grade Fatty acid esters can also be used.

Further, a polymer polyol obtained by grafting an ethylenically unsaturated compound such as styrene, acrylonitrile, or methyl methacrylate onto the above-mentioned known polyol, and a 1,2- or 1,4-polybutadiene polyol or a hydrogenated product thereof. can also be used. These polyols may be used alone or in combination of two or more.

In carrying out the present invention, polyisocyanate (component (
Adjust the amount of each raw material used so that the equivalent ratio of the NGO group contained in a)) to the active hydrogen contained in the polyol and aromatic polyamine (component (C)) is 0.8 to 1.3. do. If this equivalent ratio is less than 0.8 or more than 1.3, physical properties such as heat resistance and weather resistance of the molded product will deteriorate.

In the present invention, blowing agents, internal mold release agents, fillers, etc. as auxiliary agents of component (f) may be added as necessary, and those known in the production of polyurethane or polyurethane urea moldings by the RIM method may be used. Yes, there are no particular restrictions.

As a blowing agent, for example, trichlorofluoromethane, C
C1,F-CGIP, methylene chloride, water, nitrogen gas, carbon dioxide gas, etc.

There are various types of internal mold release agents, such as silicone-based ones, fatty acid metal salts, fatty acid amide derivatives, fatty acid ester derivatives, etc.

Fillers include glass fiber, flake glass, mica,
Examples include talc and inorganic compound whiskers.

Other auxiliary agents include pigments such as carbon, antioxidants,
There are weathering stabilizers, etc.

In the present invention, the RIV molding technique itself can be carried out according to a known method, for example, the method detailed in the above-mentioned literature, and can be carried out in various ways depending on the purpose.

The amount of reaction mixture fed into the mold is preferably such that, for example in the molding of bumpers, a molded article having a density of 0.85 to 1.15 g/c% is generally obtained. However, when mineral fillers are used, the density of the molded article can exceed 1.2 g/crrf. The molded article may remain in the mold for preferably 20 seconds or more, more preferably 30 seconds, and then removed from the mold.

Generally, the reaction mixture can be fed to the mold at a starting temperature of 25-60<0>C, preferably 30-50<0>C. The temperature of the mold itself is generally 60-120°C, preferably 60-8°C.
It is 0°C.

(Effects of the Invention) According to the method of the present invention, it is possible to produce a polyurethaneurea molded product with a dense skin that has a short demolding time, good moldability, and excellent physical properties such as shape retention, strength, and heat resistance. I can do it. Further, according to the present invention, there is no need for a RIM machine with a particularly high discharge power.

The products according to the present invention are suitable for use in a wide variety of applications such as automobile boards, sports and leisure goods, and housings for office equipment.

(Examples) Next, the present invention will be described in more detail based on Examples. The following raw materials were used in the examples.

Polyol A: Polyoxyalkylene triol with a hydroxyl value of 28 mgKOH/g and a primary hydroxyl group content of 75%, obtained by addition polymerization of 15% by weight of propylene oxide and ethylene oxide to glycerin, and a molecular weight of about 6,000 isocyanate A diphthalate. NC obtained by reacting a mixture of enylmethane diisocyanate and its carbodiimide modified product with tripropylene glycol
Repolymer with 23% O group content, molecular weight 370 Examples 1 to 4 (Sheet mold molding test) Polyol A, tert-butyltoluene leamine (Air Products Ch) with the composition (parts by weight) shown in Table 1.
A resin was prepared by mixing bismuth tris (neodecanoate) as a fatty acid salt of bismuth, and neodecanoic acid, dodecylbenzenesulfonic acid, adipic acid, or nonylphenol as an organic acid. The resin liquid was reacted with Incyanate A using a reaction injection molding machine.

The reaction injection molding machine is LRM- manufactured by Cincinnati Milacron.
L15 type was used. The mold is 900mm x 600n++
A sheet mold of ++X 3 , O+am was heated to 70°C.

The temperature of the stock solution was adjusted to 40° C., and the flow rate ratio of the resin solution to the incyanate component was adjusted to be the amount described in Table 1. Dry nitrogen gas was mixed and dispersed in the resin liquid in an amount of 15% by volume, and the mixture was injected into the mold at an injection speed of 1000 g/sec.

Demold the mold 30 seconds after injection, and determine whether the mold releasability is good (when the molded product is removed from the mold, whether or not a part of the molded product remains on the mold surface, and if no part remains, it is considered good. ), and compared the elasticity immediately after demolding. Immediately after demolding, the molded product was bent 180 degrees and the time required for no cracks to occur was measured, and the green strength was determined. Visually inspect the surface condition of the molded product, that is, the presence or absence of surface defects.The value obtained by dividing the filling length (m+a) to the tip of the sheet by the total sheet weight (g) was defined as the liquid flow index (cm/g). The larger the value of the liquid flow index, the better the liquid flow.

In addition, test pieces were cut from the molded product to determine the tensile strength, elongation,
Bending modulus and heat resistance were measured. Heat resistance test is 2c
A strip-shaped test piece measuring 15 cm x 15 cm is fixed horizontally at a position 5 cm from one end and left in a constant temperature bath at 120° C. for 1 hour. After being left standing, the distance that the other end sagged (thermal sag) was measured and the heat resistance was compared.

The results are shown in Table 2.

Comparative Example 1 Dibutyltin dilaurate and D instead of bismuth-tris(neodecanoate) and neodecanoic acid as catalysts
ABCO33L V (AirProducts a
RIM molding was carried out in the same manner as in Example 1 using the same composition except that the amount of ND Chemlcals Inc. shown in Table 1 was used. The moldability and physical properties of the molded product are
Shown in the table.

Comparative Example 2 DETDA was used as the aromatic diamine instead of tert-butyldiaminotoluene, bismuth-tris (neodecanoate) was used as the catalyst, and dibutyltin dilaurate and DABCO33L V (Ai
rProducts and Chemicals I
RIM molding was carried out in the same manner as in Example 1 with the same composition except that the amounts shown in Table 1 were used. The results obtained are shown in Table 2.

As is clear from comparing Examples 1 to 4 with Comparative Examples 1 and 2, the method of the present invention shows better molding performance and demolding performance than conventional compositions during polyurethane injection molding, It was recognized that the physical properties of the molded product, such as heat resistance, were also excellent.

Claims (2)

[Claims] (1) (a) Polyisocyanate (b) Polyether polyol having a molecular weight of 1,000 to 18,000 (c) 2,4-diamino-5-tert-butyltoluene, 2
, 6-diamino-3-tert-butyltoluene, 3,4-diamino-5-tert-butyltoluene, and 2,3-diamino-4-tert-butyltoluene (d). A method for producing a polyurethane urea molded article, which comprises reaction injection molding a mixture containing a fatty acid salt of Bi and (e) an organic acid in a closed mold. (2) A polyurethaneurea molded article obtained by the method of claim (1).