JPS6315941B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a vinyl chloride resin composition reinforced with an inorganic filler and having high impact strength. In recent years, research has been conducted in various fields on adding mechanical strength and heat resistance to thermoplastic resins by compounding them with inorganic fillers, and some of them have already been put into practical use. Regarding polyvinyl chloride, reinforcement with glass fiber is known. In addition, asbestos and acicular calcium silicate (wollastonite) are used as reinforcing fillers.
Composite materials reinforced with these fibrous fillers have enhanced tensile properties in one direction, but the tensile strength in the direction perpendicular to this is significantly reduced (anisotropy occurs due to fiber orientation). Furthermore, it has the disadvantage that impact strength, which is one of the dynamic characteristics of polyvinyl chloride, is significantly reduced. Mica is a reinforcing filler that does not have anisotropic physical properties, but it has a ratio of either vertical or horizontal length to thickness (hereinafter referred to as aspect ratio).
It was found that even when using mica with a large value, the tensile properties deteriorate and the impact strength is also significantly low. This is because the shearing force required to disperse mica in polyvinyl chloride destroys the plate-like crystals of mica, resulting in a decrease in tensile strength, and the remaining unbroken mica decreases impact strength. This is because it reduces the
Also, when vinyl chloride resin is reinforced with talc,
Although the tensile properties are strengthened and the anisotropy of the physical properties is small, the impact strength is greatly reduced like mica, and the vinyl chloride resin, talc, and the necessary stabilizers and lubricants are mixed in a super mixer. , mixing for long periods of time to fully disperse talc reduces the thermal stability of the compound;
Not only was there discoloration during molding, but the molded product was also heavily colored, resulting in a molded product with poor marketability. In addition, in order to obtain high impact resistance in such composite materials, the inorganic filler and vinyl chloride resin are mixed in advance at high speed (hereinafter referred to as premixing), then the necessary stabilizer lubricant is added, and the mixture is heated and mixed to form a compound. I needed to get it. This premixing generates a large amount of filler as dust, which is not sanitary. Therefore, premixing is unnecessary and the filler is less likely to be generated as dust, which means that inorganic fillers with high bulk specific gravity and chloride As a result of intensive studies for the purpose of obtaining a vinyl resin mixture, we found that the inorganic filler used in the present invention is a small particle size or powdered inorganic filler that is generally mixed with a thermoplastic resin, or a surface-treated inorganic filler. are generally available. Further, as described later, one of the features of the present invention is the addition of a polymer flocculant, but the benefit of this is that a plate-like filler such as mica, talc, or glass flakes is used as an inorganic filler. It is especially noticeable when Therefore, the following explanation will mainly be based on the case where talc is used as a representative example of the plate-shaped filler. When Chinese talc is ground with a super micron mill, for example, crushed talc with a distribution of 74.7% below 10μ and 59.7% below 5μ (hereinafter referred to as 74.7% talc below 10μ) can be obtained. After filling this talc into polyvinyl chloride (polymerization degree 1000, lead content) and pelletizing it, a belt with a thickness of 3 mm and a width of 60 mm is formed, and the tensile physical properties in the extrusion direction (MD) and impact strength (Dupont impact 3/ 8″, 300g equivalent half failure height cm),
Between 3 and 30% by weight, the tensile strength is approximately equal to or about 10% higher than that of polyvinyl chloride, but the Dupont impact strength is extremely low compared to polyvinyl chloride. It is effective to use talc with a specific particle size distribution to improve impact strength. The talc used in the present invention is preferably talc in which 85% or more of particles are 10 μm or less in particle size distribution measured by a centrifugal sedimentation type particle size distribution analyzer. When the talc used in the present invention is filled into polyvinyl chloride by the method described above, the impact strength is improved if the initial dispersion is sufficient. Initial dispersion of the talc requires premixing of the talc and polyvinyl chloride in a high speed mixer (eg, a Henschel mixer) for about 5 minutes. Problems with this method are that talc is generated as dust during premixing, which is unfavorable from a sanitary standpoint, and the optimum value for premixing is narrow, and the optimum value varies depending on the size and type of mixer. However, it is difficult to implement it industrially. The present invention has solved this problem, and the premix obtained by adding a polymer flocculant to an aqueous slurry of vinyl chloride resin, then adding talc, stirring, and dehydrating and drying has a large bulk density and requires no premixing. It has been found that high impact resistance can be obtained even when using the same method. The vinyl chloride resin that can be used in the present invention includes vinyl chloride alone or a copolymer of vinyl chloride and a monopolymer that can be copolymerized. unsaturated dibasic organic acids such as vinyl esters of organic acids, vinylidene fluorochloride, vinylidene chloride, symmetrical dichloroethylene, acrylonitrile, methacrylonitrile, alkyl acrylate esters, alkyl methacrylate esters, dibutyl fumarate and diethyl maleate. Copolymers with dialkyl esters, unsaturated hydrocarbons, aryl compounds, conjugated and cross-conjugated ethylenically unsaturated compounds, and the like are included. The slurry after polymerization or the cake after dehydration of these vinyl chloride resins is re-slurried,
Alternatively, a slurry of the dried resin may be used. Slurry concentration is arbitrary, but 5 to 30% by weight
Approx. Any of anionic, cationic, and nonionic polymer flocculants can be used. Acrylamide-based polymers are common, but suspending agents used in vinyl chloride polymerization, such as polyvinyl alcohol, may also be used. Also effective are methanol-soluble nylon aqueous latexes. Particularly when the inorganic filler is in the form of a plate, if a polyamide with a melting point or softening point of 200° C. or lower is used, excellent thermal stability can be obtained. The amount used is preferably about 0.05 to 0.5 parts by weight per 100 parts by weight of talc. If it is less than 0.05 parts by weight, the cohesive force will be weak and it may leak from the cloth during dehydration, and if it exceeds 0.5 parts by weight, the impact resistance will decrease due to agglomeration between talcs, which is not preferable. The key point in the method of the present invention is that a coagulant is added to an aqueous slurry of vinyl chloride resin, stirred, and then talc is added. Methods such as adding a flocculant to a slurry of vinyl chloride resin and talc, or adding a flocculant to a talc slurry and then adding vinyl chloride resin are unsuitable because the impact resistance is extremely low. Talc may be added as a powder, but it is preferable to make it into a slurry beforehand. These operations may be performed at room temperature, and the stirring conditions vary depending on the type of equipment, but it is preferable to vigorously stir using a stirrer with vertical movement. In the present invention, for the ultimate purpose of obtaining high impact resistance, it is preferable that the talc contains about 15% or less of particles with a size of 10 μm or more. An excellent method to increase the proportion of particles of 10μ or less to 85% or more is to crush the particles using a crusher belonging to the Impact mill and then classify them using an Archimedean vortex classifier. As this kind of classifier
Mikroplex from Alpine is known. In this case, adjusting the blade angle,
It is necessary to repeat the same operation several times. Other Zig-Zag rotating wall classifiers (Alpine
company) is also acceptable. Alternatively, it can be obtained by using a talcum ore that is easy to crush and passing it through a crusher several times. If necessary, talc may be surface-treated with a silane coupling agent, an organic titanate, a fatty acid, etc. before use. The content of talc in the premix of the present invention is approximately
It is preferably 30% by weight or less. If it exceeds 30% by weight, the talc will not coagulate sufficiently and the effects of the present invention will not be exhibited. Further, in order to exhibit properties as a composite material, the content should be 1% or more, preferably 5% or more. The premixes of the present invention can be processed using conventional vinyl chloride resin processing methods. Regarding the formulation, lead-based,
Any combination of tin-based, Ca-Zn-based, etc. may be used, and vinyl chloride-based resin may be mixed in to adjust the talc concentration. The mixing method used is the same as the conventional method of adding necessary ingredients and hot blending using, for example, a super mixer. The molding method may be either powder or pellet, and calender extrusion blow molding or the like may be used. This will be explained below using examples. Example 1 Talc produced in China was crushed and classified using a super micron mill, and then a micron separator and a cyclone were used to produce talc A having the particle size distribution shown in Table 1.
B, C, and D were prepared. Particle size distribution was measured using Shimadzu centrifugal sedimentation particle size analyzer CP-
50 and a 0.2% aqueous solution of (Napo ₂ ) ₆ as a dispersion at 29°C. As an example of the present invention, 850 parts by weight of an aqueous slurry containing 10% by weight of polyvinyl chloride (=1000) and 0.015 parts by weight of polyacrylamide (N-50p manufactured by Sanyo Chemical Co., Ltd.)
Add part by weight (0.1 wt% of talc) of an aqueous solution and stir at room temperature for 20 minutes, then add 15 parts by weight of talc A in Table 1, stir for another 20 minutes, dehydrate, and heat at 60°C.
The premix of Example 1 was obtained by drying for 24 hours.
As a control example, 15 parts by weight of talc A in Table 1 was added to 850 parts by weight of the aqueous slurry containing polyvinyl chloride of Example 1.
After adding parts by weight and stirring for 20 minutes to form a uniform slurry, an aqueous solution of 0.015 parts by weight of N-50p was added and stirred at room temperature for 20 minutes, followed by dehydration and drying to obtain the premix of Control Example 1.

[Table] 15 parts by weight of talc A in Table 1 was dispersed in 150 parts by weight of water, and then an aqueous solution containing 0.015 parts by weight of N-50P was added and stirred for 90 minutes at room temperature.
850 parts by weight of the polyvinyl chloride slurry used in step 2 was added thereto, stirred for an additional 20 minutes, and then dehydrated and dried to obtain the premix of Control Example 2. As an example of a formulation for processing, by weight: 1 part tribasic lead sulfate, 0.5 part dibasic lead stearate, 1.5 parts lead stearate, 0.5 part calcium stearate.
A masterbatch (hereinafter referred to as MB) is used, which is a mixture of 0.5 parts of barium stearate, 0.2 parts of polyethylene wax, 0.25 parts of CM-8000, and 0.25 parts of pigment. Example 1 5 kg of premixes from Control Examples 1 and 2 was added to 20
After mixing at high speed for 0 minutes, 5 minutes, and 10 minutes (hereinafter referred to as premixing 0 minutes, 5 minutes, and 10 minutes, respectively),
Add 200g of MB and mix at high speed until 110℃.
Then, it is cooled to 70°C to obtain a compound. For comparison, 5 kg of a mixture containing polyvinyl chloride and 15 wt% of talc A in Table 1 was blended in the same manner (reference example). These blends were processed using a 40 mmψ extruder (Tabata Kikai HU-40-28 Dalmage Screw) to produce C ₁ = C ₂
= C ₃ = C ₄ = Pelletized at 190°C, and further formed into a belt with a width of 60 mm and a thickness of 3 mm using the same extruder. This belt is pressed at 185℃ to form square pieces of 30 mm x 30 mm x 25 mm, and the falling weight strength of the Du Pont't method is measured. 3/
The half-breakage height was calculated using an 8" striking core with a 2 kg weight and expressed as a height (cm) in 300 g. The obtained results are shown in the table below.
Shown in 2. In the reference example, the temperature reaches a maximum after 5 minutes of premixing, and decreases again when the time is extended further. Since this tendency differs depending on the mixer, it is difficult to implement it industrially, but in the case of the present invention, high values can be obtained without premixing. Controls 1 and 2 both show low values. It can be seen that high values can be obtained by the method of the present invention.

[Table] Examples 2, 3, 4 Using talc A in Table 1, premixes containing 10 wt%, 20 wt%, and 25 wt% of talc are prepared in the same manner as in Example 1. This was blended with the MB used in Example 1 as shown below, mixed in a 20 super mixer under conditions of 0 minutes of premixing, and further molded to determine the Du Pont't impact strength. Talc 10wt% premix 5kg + MB212g
(Example 2) Premix with 20wt% talc 5kg + MB188g
(Example 3) Premix with 25wt% talc 5kg + MB176g
(Example 4) Also, as a reference example, talc of A and Kanevinyl S
-1001 mixture with talc 10wt% mixture 5Kg + MB212g
(Reference example 2) 5 kg of 20 wt% talc mixture + 188 g of MB
(Reference example 3) 5 kg of mixture of 25 wt% talc + 176 g of MB
(Reference Example 4) Mix and mold in the same manner as Examples 2 to 4 with the formulation.
Du Pont't impact strength was investigated. The results are shown in Table-3. Higher impact resistance can be obtained compared to the case without premixing (reference example).

[Table] Example 5 Example 1 using talc B, C, and D in Table-1
Prepare a premix containing 15wt% talc using the same method as above. As a reference example, a mixture of Kanevinyl S-1001 containing 15 wt% of talc B, C, and D in Table 1 was mixed with the same formulation as in Example 1 under the conditions of 0 minutes of premixing, and molded into Du Pon. The impact strength was investigated. The results are shown in Table 4.

[Table] Although the effects of the present invention are exhibited with particle sizes A to D, from the viewpoint of impact resistance, fine particle talc is preferable to C. Example 6, Comparative Example 3 The effect of the amount of flocculant was investigated by changing the amount of N-50P in the method of Example 1. For comparison, the effect of the amount of N-50P was investigated in the same manner as in Control Example 1. The amount of talc at the time of charging was 15% by weight, but the amount of talc in the obtained premix changes if the coagulant is insufficient, so the talc content was determined. The method involves baking the dried premix at 700°C for 1 hour and determining the talc content from the weight loss. 700℃ for talc alone
Since talc also lost 2% by weight after 1 hour of firing, correction was made. The formulation and molding conditions are the same as in Example 1.
The mixing was performed under the condition of 0 minutes of premixing. The results are shown in Table-5. In the case of the present invention, when N-50P is 0.05 wt part, dehydration loss is observed, which is somewhat insufficient, but when N-50P is 0.1 wt part or more, there is no dehydration loss and high Du Pont't impact strength can be obtained. When the amount exceeds 0.5 parts, there is a tendency for the Du Pont't impact strength to decrease, but this is thought to be due to coarsening of particles due to aggregation between talc.

[Table] On the other hand, in the control example, when N-50P is 0.05 part, there is a dehydration loss and the Du Pont't strength is high, but when it is 0.1 part, the dehydration loss is reduced but the Du Pont't strength is low. Furthermore, even if N-50P is increased, the Du Pont't strength tends to further decrease. Since talc and polyvinyl chloride coexist to coagulate, talc itself will coagulate and coarsen the particles even when N-50P is present in a relatively small amount. Example 7 The effect of the present invention was investigated by changing the type of flocculant using the method of Example 1. Coagulants include polyvinyl alcohol (PVA) and methanol-soluble nylon CM.
−8000 was used. Since CM-8000 is a solid,
A latex was obtained by dropping a 1 wt% methanol solution into a 10 times ammoniacal aqueous solution while stirring. The amount used is 0.1wt part per 100wt part of talc.
A 0.2wt portion was used. The formulation and processing conditions of Example 1 were used, and the mixing was carried out under conditions of 0 minutes of premixing. The results are shown in Table-6. In either case, high impact resistance can be obtained regardless of the number of copies used.

[Table] Example 8 Using talc A in Table 1, premixes were obtained in the same manner as in Example 1 using various polymer flocculants, and they were molded (premixed) in the same manner as in Example 1. 0 minutes) and the Du Pont't impact strength was measured. The results are shown in Table-7. It is clear that any anionic, cationic, or nonionic polymer flocculant, as well as polyvinyl alcohol, can exhibit the effects of the present invention.

【table】

Claims (1)

[Claims] 1. Production of a vinyl chloride-based composite material, characterized in that an inorganic filler is mixed into an aqueous slurry of a vinyl chloride-based resin that has been mixed with a polymer flocculant in advance, and then dehydrated and dried. Method. 2. The method for producing a composite material according to claim 1, wherein the inorganic filler is a plate-like filler. 3. The method for producing a composite material according to claim 2, wherein the plate-like filler is at least one of mica, talc, and glass flakes. 4. The method for producing a composite material according to claim 1, wherein the inorganic filler has a particle size of about 10 μm or more in an amount of 15% by weight or less. 5. The method for producing a composite material according to claim 1, wherein the polymer flocculant is nonionic, anionic, or cationic. 6. The method for producing a composite material according to any one of claims 1 to 5, wherein the polymer flocculant is a polyamide with a melting point of 200°C or less. 7. The method for producing a composite material according to claim 1, wherein the inorganic filler is mixed in the form of an aqueous slurry or suspension. 8. The method for producing a composite material according to claim 1, wherein the amount of the inorganic filler is 1 to 60% by weight in the composite material. 9. The method for producing a composite material according to claim 1, wherein the aqueous slurry of vinyl chloride resin is obtained by adding a polymer flocculant to a slurry formed after polymerizing a vinyl chloride monomer and stirring the mixture. 10. The method for producing a composite material according to claim 1, wherein the aqueous slurry of vinyl chloride resin is obtained by dispersing vinyl chloride resin in water, adding a polymer flocculant, and stirring the resulting slurry. 11. The method for producing a composite material according to claim 1, wherein the vinyl chloride resin is a vinyl chloride polymer. 12 The vinyl chloride resin is a vinyl ester of vinyl chloride and an organic acid, vinylidene fluoride, vinylidene chloride, dichloroethylene, acrylonitrile, methacrylonitrile, alkyl acrylate ester, alkyl methacrylate ester, dibutyl fumarate ester, diethyl maleate ester. The method for producing a composite material according to claim 1, which is a copolymer with at least one selected monomer.