JPS5946968B2 - Method for producing polyurethane containing glassy filler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyurethane containing a vitreous filler, and more particularly to a method for producing a polyurethane containing a vitreous filler with improved elongation at break.

Polyurethane is a polymer having urethane bonds, and is mainly obtained by condensation of isocyanate groups and active hydrogen groups.

In the following, polyurethane-forming raw materials are defined as isocyanate compounds having at least 2 isocyanate groups and at least 2
This mainly indicates active hydrogen compounds having active hydrogen, and the details thereof will be described later. Polyurethanes obtained from polyurethane-forming raw materials are used in a variety of applications, particularly in molded articles such as foams, elastomers, and thermoplastic fats. The polyurethane used for these molded products is sometimes filled with a vitreous filler. The vitreous filler is a filler made of silicic acid inorganic glass, such as glass fiber, glass flakes, glass powder, and glass beads. Among these, fibrous fillers and flat fillers are particularly effective in improving the physical properties of synthetic fats and fats, particularly in improving the strength and modulus of elasticity, and are used as reinforcing fillers for synthetic resins. Powder to granular fillers are mainly used as fillers, but they also have the effect of reinforcing synthetic resins. When polyurethane is filled with the above-mentioned fillers, the strength and elastic modulus are improved, but the oxidation effect is particularly noticeable when filled with fibrous fillers or flat fillers. However, on the other hand, there is a problem in that the elongation at break of polyurethane decreases when a glassy filler is filled. For example, polyurethane elastomer alone has a large elongation rate in tensile strength tests, whereas polyurethane elastomer filled with a glassy filler has a small elongation rate. . This is equivalent to a decrease in the physical properties of the elastomer. Therefore, in the case of polyurethane elastomers, it is often desired that they be filled with a glassy filler to improve their strength and elastic modulus while at the same time minimizing the decrease in elongation at break. Similarly, even for foams with high elongation, such as flexible polyurethane foams, it is considered preferable that the elongation at break is less reduced by filling with a glassy filler. Reaction injection molding (Reac injection molding) is a method for simultaneously manufacturing and molding polyurethane.
tiOnInjectiOnMolding) is attracting attention.

This is a molding method in which at least two components, a liquid component containing an isocyanate compound and a liquid component containing an active hydrogen compound, are mixed just before the mold, and the mixture is immediately injected into the mold and cured by reaction within the mold to obtain a polyurethane molded product. be. This method is
Molding has many features such as low injection pressure as it is injection of liquid components, less heat energy required as there is no need to heat and melt the resin, and the ability to obtain molded products directly from polyurethane forming raw materials. It is expected that this method will become widely used in the future. A method of molding filler-containing polyurethane using this reaction injection molding (hereinafter referred to as RIM) method has been studied. The biggest challenge is to obtain fiber-reinforced polyurethane molded products by using glass fillers such as milled glass fibers and chopped strands as VfVC fillers. This fiber-reinforced polyurethane R
Regarding the IM method, some proposals have already been made regarding the apparatus and method, and the length and diameter of the glass fibers used for this purpose, the amount of filling thereof, etc. are also being studied. However, the problem of the reduction in elongation at break in glassy filler-containing polyurethanes produced by the RIM method has not yet been sufficiently investigated, and no solution has been presented. Using a corresponding method, polyurethane containing a glass filler such as glass milled fiber was molded, its tensile strength and tensile strength ratio were measured, and the elongation rate at break was measured. Therefore, various research studies were conducted in order to find a polyurethane containing a glassy filler that exhibits less reduction in elongation at break.

In order to improve the physical properties of synthetic resins containing general fillers, there are methods of surface treatment of fillers and methods of adding additives to synthetic resins. The present inventors have now investigated a method of obtaining desired physical properties by adding additives. This is because this method is considered to have a wider range of applicability because it is a simple method of simple addition compared to a method using surface treatment. The present inventor conducted research and examination on various compounds in order to find additives that can improve the elongation at break of polyurethane containing glassy fillers, and as a result, it was found that zinc salts and calcium salts of long-chain alkyl carboxylic acids are effective. I discovered that. The gist of the present invention is a method for producing a glassy filler-containing polyurethane using this additive,
That is, a vitreous filler-containing polyurethane is produced by a reaction injection molding method by reacting an isocyanate compound having at least two isocyanate groups with an active hydrogen compound having at least two active hydrogens in the presence of a vitreous filler. Method Vc. In particular, it is a method for producing a vitreous filler-containing polyurethane with improved elongation at break, characterized by the presence of a long-chain alkyl carboxylic acid metal salt together with the vitreous filler. The term "elongation at break improved" means that the rate at which the elongation of polyurethane decreases due to the addition of the vitreous filler is small.

The elongation of polyurethane containing no vitreous filler is large, but the elongation decreases as the amount of vitreous filler increases. The rate of elongation is measured by subjecting the test piece to a tensile test and measuring the ratio of the length at which the test piece breaks to the original length of the test piece. This elongation at break is not proportional to the tensile strength. For example, some materials have high tensile strength but low elongation at break. Generally, when filled with fibrous fillers such as glass fibers, the tensile strength of polyurethane can be greatly improved, but the elongation at break often decreases. tends to decline. An object of the present invention is to improve the elongation at break without significantly inhibiting the improvement in physical properties such as tensile strength due to the addition of a vitreous filler. The additive in the present invention is a metal salt of a long-chain alkyl carboxylic acid. A long-chain alkyl carboxylic acid is a carboxylic acid having an alkyl group having 8 or more carbon atoms, especially a straight-chain alkyl group, and has the general formula CnH2n. f. It is expressed as ICOOH (n: similar to above).

The carbon number n of the alkyl group is preferably 10 to 20.
Specific compounds include, for example, stearic acid, palmitic acid, and lauric acid, with stearic acid being particularly preferred. The metal ions that form salts with this acid are 2
-Trivalent metal ions, particularly divalent metal ions, are preferred. As specific metals, zinc, calcium, zirconium, lead, magnesium, aluminum, etc. are preferable, and zinc and calcium are particularly preferable. Moreover, this salt may be a basic salt. This long-chain alkyl carboxylic acid metal salt does not have to be pure; for example, commercially available zinc stearate, which contains zinc palmitate and a large amount of zinc oxide, can also be used. The amount of these additives added is not particularly limited as long as the additive effect can be exhibited and the molding of the polyurethane is not inhibited.

However, the amount usually used is 10% by weight or less, particularly 0.005 to 5% by weight, based on the vitreous filler. That is, as shown in the examples, when the amount of vitreous filler in the molded product is 20% by weight, the amount of additives contained in the molded product is 2% by weight or less, particularly 0.1 to 1% by weight. Weight % is appropriate. Although the effect of improving the elongation at break is not limited, it is preferable that the elongation is 1.5 times or more, particularly 2 times or more, compared to the elongation when no additive is included. The additive is added to the polyurethane before the reaction of the polyurethane-forming raw material mixture is completed, that is, before the polyurethane-forming raw material mixture hardens and forms polyurethane.

Preferably, it is added in advance to one or both of the at least two types of polyurethane forming raw materials, or it is appropriate to crush them at the same time when the polyurethane forming raw materials are mixed. Further, the addition of the vitreous filler and this additive may not be simultaneous. For example, a method in which this additive is added to one of at least two types of polyurethane forming raw materials and a vitreous filler is added to the other, or a method in which this additive is added to at least one of the polyurethane forming raw materials and the polyurethane forming raw materials are mixed. At this time, a method of mixing a vitreous filler, a method of impregnating or mixing a polyurethane-forming raw material mixture containing this additive into the vitreous filler, and other methods can be used. Of course, there is a method of adding both at the same time, for example, a method of adding the additive and the vitreous filler to one of the polyurethane forming raw materials in advance, and a method of adding the mixture of the additive and the vitreous filler to at least one of the polyurethane forming raw materials. A method of adding it to a mixture thereof or a mixture thereof, or other methods can be used. In short, the ``presence'' of this additive ``along with the vitreous filler'' does not indicate the timing of addition, but rather that both are present in the polyurethane-forming raw material mixture before the end of the reaction of the polyurethane-forming raw material mixture. It shows that it exists. Therefore, this additive can also be added to polyurethane forming raw materials other than the isocyanate compound and the active hydrogen compound, such as a blowing agent. The vitreous filler used in the present invention includes glass fibers, glass flakes, glass beads, glass microballoons, glass powder, etc. Glass fibers having a particularly high reinforcing effect are particularly suitable.

Taking glass fiber as an example, there are various forms of glass fiber, but when used in the RIM method, it needs to flow easily with the polyurethane forming raw material, so milled glass fibers and chopped strands are suitable. It is. Similarly, when impregnating polyurethane forming raw materials or mixtures thereof, or after filling a mold with glass fibers in advance, RIM
When a polyurethane-forming raw material mixture is introduced by a method, its form is not particularly limited, and for example, roping, chopped strand mat, continuous strand mat, roping cloth, cloth, etc. can also be used. In addition, in the present invention, not only one type or one form of the vitreous filler may be used, but also two or more types or two or more forms of the vitreous filler may be used. The vitreous filler, like the additive in the present invention, is used when the reaction of the polyurethane forming raw material mixture is completed.
It is present in the polyurethane-forming raw material mixture before bedtime.

In particular, in the case of the RIM method, at least two types of liquid polyurethane forming raw materials are mixed in advance with one or more of them and RIM molding is performed, or at least two types of fluidizable components including a glassy filler are used as a third component. It is preferable to use a method of simultaneously mixing the polyurethane forming raw materials during mixing and injection, or a method of performing RIM molding by mixing the polyurethane forming raw materials into the polyurethane forming raw material mixture immediately after mixing and injection. The amount of vitreous filler to be filled in polyurethane is not particularly limited.

However, in the case of RIM molding, a certain level of fluidity is required for the vitreous filler and components containing it to be injected into the mold, so the filling amount is often limited. Usually less than 50% by weight of the molded product, usually 5~
It is filled at about 30% by weight. Of course, more may be filled if possible. RIM of filled polyurethane
Although various RIM methods can be considered for production, the following two methods are preferably used.

One method is to disperse a filler in advance in at least one of at least two types of polyurethane forming raw materials, and then molding the polyurethane forming raw material containing the filler by the RIM method.

For example, a filler is dispersed in a component containing an active hydrogen compound such as a polyether polyol, and molding is performed using this component and a component containing an isocyanate compound by the RIM method. Of course, the component to which the filler is added in advance may be a component containing an isocyanate compound, or it may be added to both components together. Another method is to perform the RIM process using a filler-containing component as the third component. In the RIM method, two components, a component containing an isocyanate compound and a component containing an active hydrogen compound, are mixed and injected in many cases, but three or more components can also be mixed and injected. Therefore, using this method, a filler-containing and fluidizable component can be mixed and injected as a third component with two or more components.
There are two possible methods for this method; one is to mix the third component at the same time as the other components;
Another method is to mix the third component into the mixture immediately after mixing the other components. This third component is suitably a mixture of a filler and a liquid component or a fluidizable solid component, and it is preferable to use a part of the polyurethane forming raw material, such as an active hydrogen compound, as the liquid component. The polyurethane in the present invention is a polymer having urethane bonds, and often contains urea bonds, biuret bonds, allophanate bonds, etc. in addition to urethane bonds. Furthermore, polymers containing many bonds other than urethane bonds, such as polyisocyanurate, are also included. This polyurethane bond is formed by a reaction between an isocyanate group and an active hydrogen group. A blocked or masked isocyanate group does not directly react with an active hydrogen group, but once an isocyanate group is generated and reacts, it is considered as one type of isocyanate group in the present invention. Polyurethane is formed from at least two polyurethane-forming raw materials. One of them is an isocyanate compound having at least two isocyanate groups, and the other one is an active hydrogen compound having at least two active hydrogens.
Each of the isocyanate compound and the active hydrogen compound may be a mixture of two or more kinds of compounds. The reaction between an isocyanate compound and an active hydrogen compound usually requires a catalyst, and basic catalysts such as amines and organometallic compounds such as organotin compounds are often used. Isocyanate compounds include aromatic, aliphatic, alicyclic, and heterocyclic hydrocarbons having at least two isocyanate groups, as well as isocyanate-terminated prepolymers and modified isocyanate compounds modified with various compounds. There are compounds that are masked or blocked.

In particular, aromatic polyisocyanates such as TDI, MDI, PAPI and others are often used. Although there are many types of active hydrogen compounds, compounds having a hydroxyl group, that is, polyols, are most often used. For example, polyether polyols and polyester polyols.
There are also block polymers such as polymer polyols, polymer-containing polyols, hydroxyl group-containing polybutadiene, acrylic polyols, and other polymers. In addition, active hydrogen groups other than hydroxyl groups include amines and others, such as polyols treated with amines and ammonia.
In addition, relatively low molecular weight polyols and amine compounds are also called crosslinking agents or chain extenders, and are often used as a type of raw material for elastomers and foams. Many more additives are used as raw materials other than the isocyanate compound, active hydrogen compound, and catalyst. For example, foams require blowing agents and blowing agents. Other additives include, for example, colorants, mold release agents, stabilizers,
Fillers other than flame retardants, softeners, and glass fillers.
Fillers other than vitreous fillers include fibrous fillers such as carbon fibers and synthetic fibers, and powder fillers such as calcium carbonate, barium sulfate, and aluminum hydroxide, which can be used in combination with vitreous fillers. can. EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples.

Example 1 Glass fiber milled fiber (average length 140 μm, fiber diameter 14 μm, E-glass manufactured by Asahi Fiberglass Co., Ltd., trade name “MF-B”) was manufactured so that the glass fiber content in the final molded product was 20% by weight. Put the amount of 10m77Z into a pressure-resistant container.
After degassing under reduced pressure of Hg, 36 parts by weight of polyether polyol (molecular weight: about 4000, number of functional groups: 2: manufactured by Asahi Olin Washing Co., Ltd.) was added dropwise under the same pressure, followed by stirring.

A second polyether polyol (molecular weight approximately 6500, number of functional groups 3: manufactured by Asahi Olin Products) 3 was further added to the obtained mixture.
6 parts by weight of 1.4-butanediol, 28 parts by weight of 1.4-butanediol, and zinc stearate were added in amounts such that the content in the final molded product would be as shown in Table 1 below, and the mixture was similarly stirred under reduced pressure.

To this polyol system liquid, an amount of modified MDI (trade name: Isonate-143L manufactured by Kasei Updition) was added to give an isocyanate isodex of 106, and after stirring under reduced pressure in the same manner, predetermined amounts of triethylenediamine and dibutyl were added. Tin dilaurate was added as a catalyst, stirred for several seconds, and immediately shot into a mold.

After reaction curing, a polyurethane elastomer having a glass fiber content of 20% by weight and a zinc stearate content as shown in Table 1 below was obtained. This method is known to be equivalent to molding polyurethane elastomers by the RIM method (although the elongation value is higher), and by evaluating molded products obtained by this method, it was found that molding of polyurethane elastomers by the RIM method Physical properties can be evaluated.

The density, flexural modulus, tensile strength, and elongation at break of this molded article were measured. Measurements were performed using the following method. Table 1 below shows the measured values obtained by changing the amount of zinc stearate added.
Example 2 The results of the same experiment as in Example except that calcium stearate was used instead of zinc stearate were used in the second example.
Shown in the table.

Claims (1)

[Claims] 1. Reaction injection of a polyurethane containing a glassy filler by reacting an isocyanate compound having at least two isocyanate groups with an active hydrogen compound having at least two active hydrogens in the presence of a glassy filler. With the molding method,
A method for producing a vitreous filler-containing polyurethane with improved elongation at break, characterized in that a long-chain alkylcarboxylic acid metal salt is present together with the vitreous filler. 2. The method according to claim 1, wherein the long-chain alkyl carboxylic acid metal salt is a zinc salt or a calcium salt of a long-chain alkyl carboxylic acid. 3 Long chain alkyl carboxylic acid metal salt has 10 to 20 carbon atoms
2. The method according to claim 1, wherein the metal salt is a straight-chain alkyl carboxylic acid. 4. The method according to claim 1, wherein the vitreous filler is glass fiber.