JPH0659664B2 - Reinforcement-containing reaction injection molding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a reinforcement-containing reaction injection molding method for a urethane resin containing potassium titanate whiskers as a filler.

[Conventional technology]

This type of reinforcement-containing reaction injection molding (hereinafter referred to as R / RIM) is well known from JP-A-61-20717, whereby needle-like crystal filler particles are micro-dispersed in the R / RIM raw material, and As a result, a smooth molded product can be obtained, and thus a product having excellent coating smoothness and sharpness after painting can be obtained.

[Problems to be solved by the invention]

However, potassium titanate whiskers, when mixed with resin raw materials (polyol and isocyanate), can be mixed only in the polyol because of the potassium content normally contained in the whiskers, and when mixed in the polyol, the amount of mixing increases. There is a problem of thickening with it. Therefore,
Like other reinforcing materials, it is difficult to make urethane resin contain about 12 to 20 wt%, which leads to dimensional stability and strength.
There was room for improvement in terms of improving material properties such as rigidity.

In other words, potassium whisker titanate is a monoclinic acicular microcrystal, which has a large surface area per unit weight and a large contact area with a polyol. For this reason, the amount of polyol adsorbed and fixed to the surface functional group (oxygen) of potassium titanate is much larger than that of other glass flakes or mica flakes. Therefore, there is a large increase in viscosity as the amount of mixture increases,
The dispersibility decreases with an increase in the mixed amount.

In a commonly used propeller agitation mixer, potassium titanate whiskers rapidly increase in viscosity from about 10% in the urethane resin even when the polyol is mixed while heating (50 to 60 ° C), and the dispersibility is increased. The number of whiskers is decreased, and an aggregate of dozens or more whiskers is generated, and a molding defect called a lump after molding is generated. Mixing into the polyol is limited to 12% by weight in terms of content in the urethane resin.

Therefore, by the simultaneous patent application by the applicant of the present invention, it will be described later in the raw material mixed solution so that the increase in the mixing amount of potassium titanate whiskers in the polyol to an effective amount as a urethane reinforcing agent can be suppressed. A reinforcement-containing reaction injection molding method in which a surfactant of chemical formula is contained is proposed.

However, as long as the potassium titanate whiskers are used as the reinforcing material, even if the strength / rigidity, dimensional stability, etc. are improved, the problem that the directionality of the physical properties remains, like other fiber materials, remains. Become. That is, the bending elastic modulus, Izod impact strength, thermal expansion coefficient, and molding shrinkage rate in the direction perpendicular to the longitudinal direction of the whisker were inferior, and there was room for improvement.

Therefore, the present invention can suppress the thickening even if the amount of potassium titanate whiskers mixed into the polyol is increased to an effective amount as a urethane resin reinforcing material, and further, the reinforcing material-containing reaction injection that has as little directionality as the reinforcing effect. An object is to provide a molding method.

[Means for solving problems]

The present inventors have found that when mica flakes are used as a reinforcing material in addition to potassium titanate whiskers, and the same surfactant as that used in the invention of the above-mentioned simultaneous application is present together with this mixed reinforcing material, the above-mentioned object is obtained. I have found that I can achieve it.

This surfactant is therefore a phosphoric acid ester adduct of polyoxyethylene alkyl phenyl ether,
It has the following chemical structural formula:

Here, R: alkyl group R ′: H or Further, it was confirmed that the number n of addition moles of etileoxide is preferably 8 to 11.

The surfactant of the present invention may be added to the polyol,
Alternatively, potassium titanate whiskers or mica flakes may be treated in advance with this surfactant to make them adsorbed on the surface, and this may be mixed in the polyol. In this case, the same effect can be obtained even if the amount of the surfactant in the polyol is reduced.

[Action]

It is considered that this surfactant covers the hydrophilic groups on the surfaces of the potassium titanate whiskers and the mica flakes to prevent the adsorption of the polyol and thus suppress the increase in viscosity.

Example of Invention

 Next, the present invention will be described based on Examples and Comparative Examples.

First, the following polyols, potassium titanate whiskers, mica flakes, and surfactants (dispersants) having the following product names are weighed and mixed for 3 minutes using a homodisperser (propeller rotary high-speed stirring mixer), and a reinforcing material. The relationship between the mixing amount and the viscosity of the reinforcing material-containing polyol was measured at a liquid temperature of 40 ° C.

Polyol Sumitomo Bayer Urethane Premix for Bayflex 110-80 IMR Polyol M-375 Reinforcement Otsuka Chemical Potassium Titanate Whisker, Tismo D-105 Mascobite Mica Flakes I-350 AT, Average Thickness 0.8 μm Average Diameter 28 μm K ₂ Al ₄ (Si ₃ Al) ₂ O ₂₀ (OH) ₄ dispersant Prysurf H-3051 (n = 11) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Dispersant addition amount 7% (wt% relative to the reinforcing material) Viscosity measuring method JISK1557, 6-3 Compliant with the method (BL type viscometer) Amount of reinforcing material mixed out of 100 parts by weight of polyol
The wt% diagram shows the viscosity measurement results for such a mixture. In the figure, in the example, when the weight ratio of the aforementioned potassium titanate whiskers and mica flakes to be mixed is 100: 125,
Comparative Example 1 is the case where only the above potassium titanate whiskers without the addition of a dispersant are mixed, Comparative Example 2 is the case where the above potassium titanate whiskers and mica flakes without the addition of a dispersant are mixed, and Comparative Example 3 is the dispersant. This is the case of mixing only the above-mentioned mica flakes without addition.

As can be seen from the figure, in the case where the dispersant according to the present invention is not added, not only the potassium titanate whiskers but also the mica flakes are mixed, the viscosity rapidly increases with the increase of the mixing amount. Further, in the case of only the mica flakes without the addition of the dispersant, the increase in viscosity is slow, but compared with the examples, the viscosity sharply increases from the vicinity of the upper limit of the moldable region shown by the dotted line.

Injection Molding Example Using the reinforcing material-containing polyols of Examples I to V and Comparative Examples I to IV in which the mixing amount of the reinforcing material shown in Table 1 with respect to the raw material polyol was variously changed, an internal mixing reaction injection molding machine was used. Injection-molded products (600 x 7
00 × 3mm plate material) was produced.

a. Reinforcement material b. Urethane raw material c. Mixing ratio d. Molding condition The test is performed for each test item shown in Table 5 by the method of Table 6, and the results are shown together in Table 5. However, regarding coatability, an undercoating using a one-component polyurethane paint on the molded product by air spraying or a coating method (film thickness 15 to 20 μm) and an overcoat with a one-component melamine polyester paint (film thickness 15 to 40).
.mu.m) and baked at 110.degree. C. for 20 minutes and 120.degree. C. for 30 minutes, respectively, and then tested.

e. Test results f. Test method As can be seen from the results, by mixing potassium titanate whiskers and mica flakes in the polyol together with the specific anionic surfactant according to the present invention, avoiding thickening due to an increase in the amount of the reinforcing material mixed, and mixing an effective amount. Is not only allowed, but the surface condition of the molded product is maintained at the same level as before, and as the amount of the reinforcing material mixed increases, the direction parallel to the resin flow on the plate surface, that is, the statistical arrangement of whiskers It can be seen that the bending elastic modulus, the Izod impact strength, the expansion coefficient and the molding shrinkage coefficient are improved not only in the longitudinal direction but also in the orthogonal direction. In particular, the flexural modulus which can be obtained only in the longitudinal direction of potassium titanate whiskers alone is achieved by using almost half the whiskers and showing a significantly improved value in the vertical direction.

The present invention can be applied not only to high elastic modulus but also to medium or low elastic modulus. Therefore, it can be used not only for the outer plate of the vehicle body but also for its exterior parts such as a soft facer, a large side protector molding, and a side mat guard.

〔The invention's effect〕

As described above, according to the present invention, it is possible to increase the content of both the potassium titanate whiskers and the mica flakes in the urethane resin injection molded product as a reinforcing material, without causing surface defects such as agglomerates and swelling. In addition, the flexural modulus in the vertical direction as well as the parallel direction, strength / rigidity characteristics such as Izod impact strength, and dimensional stability due to thermal expansion / molding shrinkage are greatly improved. As a result, a higher quality urethane molded product can be realized, for example, for fenders of vehicle body outer plates and door outers.

BRIEF DESCRIPTION OF THE DRAWINGS The figure shows the relationship between the amount of reinforcing material mixed and the viscosity of the reinforcing material mixed polyol according to the examples and comparative examples of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takami Fujishita 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor, Kanemitsu Kondo 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd.

Claims (1)

[Claims] Claims: 1. A reinforcing material-containing reaction injection molding method in which a mixed solution containing a polyol, an isocyanate and potassium titanate whiskers as a filler is injected into a mold and reacted to obtain a molded article, wherein the mixed solution further comprises mica flakes and the following: Formula surfactant Here, R: alkyl group R ′: H or The method characterized by containing.