JPS60262854A - resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. with reduced raw material cost and improved physical properties and freed from the problem of causing deformation after molding, by mixing anhydrous gypsum having a controlled moisture content and potassium titanate whisker with a thermoplastic resin. CONSTITUTION:10-60pts.wt. anhydrous gypsum with adherent moisture content adjusted to several % and 5-30pts.wt. potassium titanate whisker are mixed with 100pts.wt. thermoplastic resin. The potassium titanate whisker is a white needle crystal having an average fiber length of 10-20mu and a fiber diameter of 0.2-0.5mu obtd. from a mixture of K2CO3 and TiO2 by firing, melting, a hydrothermal process or a flux process. Pref. the mixing order is such that gypsum is previously mixed with the whisker and the mixture is then mixed with the resin, whereby the filling ratio of gypsum can be improved.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a resin composition containing a thermoplastic resin as a main raw material.
! Compared to conventional thermoplastic resin molded products, molded products that can be crushed have lower raw material costs, improved physical properties such as tensile strength, bending strength, rigidity, and heat resistance, and are less prone to warping, sink marks, etc. after molding. It has the property of almost no deformation, and is widely used in applications where conventional thermoplastic resin molded products have been used, such as building materials and household goods.

(Prior art) Previous attempts have been made to manufacture composite molded products using a mixture of gypsum powder and a layer of thermoplastic steel such as vinyl chloride as a raw material, with the main purpose of reducing material costs and improving heat resistance. Currently, the desired effect cannot be obtained due to the reasons described below.

(Problems to be Solved by the Invention) (1) The mixing ratio of gypsum powder is limited. By mixing gypsum powder, the flow of the molten resin/'J'' becomes extremely poor, resulting in extremely poor workability. Taking extrusion molding as an example, if the mixing ratio of stone powder to 100 parts of resin is 30 parts, molding becomes almost impossible, and the possible mixing ratio at normal production pace is 10 parts. The limit is 20 parts by weight.Moreover, even in the case of 20 parts by weight, the shape of the molded product is currently subject to restrictions.In other words, the shape of the molded product is limited to 3 parts or less in thickness. In contrast, the content of Gyosho powder is further reduced to a limit of 10 parts by weight or less.These phenomena are caused by poor compatibility between gypsum powder and thermoplastic resins such as vinyl chloride. Unless this poor compatibility is corrected, there will be a sufficient filling rate to impart to the molded product various mechanisms that are expected to appear when mixed with a thermoplastic resin such as gypsum powder. With this, it becomes almost impossible to mix and mold gypsum powder with thermoplastic resin.

(11) When gypsum powder is mixed with a thermoplastic resin that has significantly poor impact resistance, it is expected that physical properties will be improved, such as improved rigidity, improved heat resistance, and reduced coefficient of thermal expansion. However, on the contrary, the impact resistance is significantly inferior, and at present it is not possible to increase the filling rate enough to achieve the desired effect. If we take vinyl chloride as an example of a thermoplastic resin that is the main raw material, the impact resistance will deteriorate due to the mixing of gypsum powder.When the amount of gypsum powder mixed is 10 parts by weight and -20 parts by weight, τ ~ 4. It becomes 10. The biggest cause of this phenomenon is
Weak strength at the interface between the vinyl chloride resin matrix and the gypsum filler, and poor dispersibility of gypsum powder in the molten resin, i.e., partial overcrowding (agglomeration).
It is thought that localization of the state and depopulation state is a major factor.

(110 Melting with poor surface properties [111 The main causes are poor dispersibility of gypsum powder in R and poor compatibility between gypsum powder and molten resin.] The surface of the molded product that is produced is almost matte.Therefore, if a saturated design is required, a cross-like appearance must be imparted by painting in a separate process. This leads to higher costs.Vinyl chloride resin 1
Taking as an example an extrusion molded product obtained by mixing 20 parts by weight of gypsum powder as a raw material, if gypsum powder is not mixed, the average surface roughness of the molded product after passing through sizing is The current situation is that the mixed material has a limit of 2μ to 3μb', whereas the diameter is 05μ.

As mentioned above, the idea of obtaining a molded product using a mixture of thermoplastic resin and gypsum powder as a raw material using a method similar to a normal thermoplastic resin molding method is as follows: (2I) The resulting molded product The cost of raw materials for products is reduced (1
)) Improved rigidity (tcl) Reduced thermal expansion coefficient (dl) Although it has many advantages such as improved heat resistance, there are still many problems that remain unsolved with current and conventional technology. is the current situation.

Therefore, the present inventor conducted repeated research to solve the three problems in the prior art described above, and as a result, came up with the present invention.

(Means for solving the problems) As mentioned above, the problems of the current technology caused by mixing gypsum powder with thermoplastic resin are approximately the following six problems.
It can be summarized into points.

(1) Poor dispersibility of gypsum powder in molten resin 11)
Compatibility between gypsum powder and molten resin η(iiD) The interface between gypsum powder and molten resin is weak in strength, so in order to solve these six points We searched for an additive that could act as an intermediary to improve the dispersibility, compatibility, and mechanical strength of the interface. Adjust the powder and add titanium acid to thermoplastic, 1111
It has been found that the above-mentioned problems can be considerably improved by mixing the above-mentioned materials with

Titanium acid force 11umwiss force - I K Co and TiO
The average fiber length is 10 to 20, which is obtained by using a mixture of
It is a white needle-like crystal with a fiber diameter of 02 to 05 μm, and has the following features.

fa) Excellent heat insulation, acid resistance, and alkali resistance.

(b) It is hydrophilic in itself.

(c) Since it is fine, the increase in viscosity of the molten resin is also low.

(d) Even when molding a complex shape, dispersion and reinforcement can be applied to every corner.

(e) Since it is relatively soft among inorganic fibers, it causes less wear and damage to processing and molding machines and molds.

(fl INN Since the flame length is short and the increase in viscosity is small, there is less orientation in the molded product and less warpage and sink marks.

(GL is expensive as a filler.

Among the above-mentioned features, the following are particularly preferable for the purpose of the present invention: (a), (b), (c), (d), fe
). The detailed reason for this is that the affinity with b'-1 gypsum powder, which will be described later, is due to its hydrophilic property.

Compatibility with the molten resin is given by the properties shown in (d), and improvement in processability is given by the properties shown in fa) and (c) K, respectively.

In addition, potassium titanate whisker alone is expensive as described in (e), so its range of use as a filler for thermoplastic resins is extremely limited. By combining 11um whiskers and gypsum powder, it becomes possible to mix gypsum powder, which is itself inexpensive, at a high filling rate, which makes it possible to mix titanic acid, which is expensive and has little utility value. The utility value of Power 11 Um Whisker will increase.

Thermoplastic resins to which the present invention can be applied include homopolymers such as polyethylene, polyvinyl chloride, Bo II propylene, acrylinide 11-butadiene-styrene terpolymer, or acu-1]mer, or Bo-11-mer. Blends and the like are possible, and anhydrous gypsum is preferably used as the gypsum powder. Add 11 um titanium acid whiskers to the gypsum powder, which has been adjusted to have adhering water on the order of a few percent, in a ratio suitable for the product design at home, and premix it using a high-speed stirrer, etc. and then mixed with thermoplastic resin powder or pellets to obtain a resin composition. Note that the order in which they are mixed with the resin may be arbitrary, but it is preferable to mix the gypsum and whiskers in advance and then mix them with the resin at the same time because the filling rate of the gypsum will be better.

By using the same molding method (extrusion molding, injection molding, etc.) as the usual thermoplastic V14 resin molding method for the resin composition described above, the processability is improved despite the fact that K is mixed with gypsum powder. Obtain a molded product with improved physical properties such as excellent impact resistance, no significant deterioration in impact resistance, a large degree of freedom in five shapes with a smooth surface, excellent heat resistance, and less warping and sink marks after molding. becomes possible.

(Action) and (Effect of the invention) Here, the present invention I! 1' - What points and why the present invention has advantages when compared with the prior art will be explained in detail based on the description in the (Prior Art) section.

(1) There is a limit to the mixing ratio of gypsum powder It was already mentioned in the section (Prior Art) that this phenomenon is caused by poor compatibility between gypsum powder and molten resin. However, when potassium titanate whiskers are added here, since potassium titanate whiskers themselves have hydrophilic properties and are acicular crystals, a few percent of potassium titanate whiskers are added when premixing gypsum powder and potassium titanate whiskers. adsorbed on the gypsum powder in the presence of adhering water. The potassium titanate whisker itself has good compatibility with the resin. When this mixture is mixed into a thermoplastic resin, melted and kneaded, the gypsum powder adsorbed by the potassium titanate whisker becomes more soluble than when it is bare. It has good compatibility with the melting crab tree 1 yen, and high filling becomes possible.

(11) This phenomenon of extremely poor impact resistance is caused by the weak strength at the interface between the gypsum powder and the thermoplastic resin and the poor dispersibility of the gypsum powder in the molten resin.

In the case of the present invention, the gypsum powder is in the form of being adsorbed by titanium acid 11um whiskers, and titanium acidity II
As it is known that the r'7 mu whisker and the resin have good affinity, the strength of the interface is significantly improved compared to when using gypsum powder alone. In addition, regarding the poor dispersibility, the dispersibility of the titanium acid 11 um whisker is within the range of thickness, and is considerably improved.

From the above, by adding 11% of titanium acid, it is possible to suppress the deterioration of impact resistance.

Taking vinyl chloride resin as an example, 1/1 of the amount of gypsum powder
The addition of whiskers in step 2 reduces the deterioration of impact resistance by about 2/2.
We have confirmed that it can be kept to 3.

(110 This phenomenon of poor surface properties is also mainly caused by poor dispersibility and poor compatibility of gypsum powder, and by applying the present invention, it can be improved by the mechanism described so far. It has been confirmed that the average surface roughness is improved by about 30-50% by adding potassium titanate whiskers in an amount equal to the amount of gypsum powder added.

As mentioned above, in order to solve the problems of the prior art that occur when molding a mixture of gypsum powder and thermoplastic resin, it is necessary to adjust the ratio of gypsum powder and titanium acid whiskers to a desired ratio. It can be improved considerably by combining them. In addition to the above-mentioned improvements, the synergistic effect of the combination of gypsum powder and titanium acid power 1) ram produces the following numerous advantages.

■ Both gypsum powder and titanium acid ram whiskers can be used as fillers that improve bending strength, flexural modulus, dimensional stability, etc. Due to the synergistic effect, the above-mentioned physical property values of molded articles using the composition obtained by the present invention are better than those found in conventional fillers.

■ If it becomes possible to mix 6 liver powder into a thermoplastic resin at a high filling rate, it is expected that its heat resistance will be considerably improved. With conventional technology, as mentioned above, there was a limit to the filling rate of gypsum powder at low levels.
Although it was not possible to obtain a molded product in which the expected improvement in heat resistance was reflected in the physical property values, application of the present invention made it possible to produce a composite molded product with a considerably high filling rate. It has also been confirmed that the heat resistance is considerably improved compared to the original thermoplastic resin, which is the main raw material.

So far, the effects of the present invention and the principles that bring about the effects have been explained, but in order to explain the present invention more clearly, specific examples will be described below. Needless to say (the present invention is not limited to this example)
, many kinds of application examples b' can be devised from its essential principle.

(Example) Using a mixture consisting of formulation A, formulation B, and formulation C shown below as raw materials, a plate with a width of 5 degrees and a thickness of 4 degrees was extruded using a twin-screw extrusion machine, and the physical properties of each were extruded. Table 1 shows the results of measuring the values.

(Formulation A) (Formulation B) (Formulation C)
.

(The conditions were 15o1 rpm in a super mixer for 05 hours) x Extrusion conditions [extruder] Sufu 11, -I! Diameter 30y, 2
Layout of each part of the extruder in different directions

Claims (1)

[Claims] Anhydrous gypsum and titanium acid 11 um whiskers, which have been adjusted so that several percent of adhered water exists, are added to a thermoplastic resin with 10 to 60 parts by weight and 5 to 5 parts by weight, respectively, per 100 parts by weight of the resin. A resin composition characterized by being mixed at a ratio of 30 parts by weight.