JPH0569855B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for manufacturing a plastic sheet in which a fibrous filler is dispersed. [Prior Art] A method for producing fiber-reinforced thermoplastic sheets by compression molding, in which a fibrous filler and matrix resin powder are mixed and stirred in a gas phase, and the resulting mixture is heated and pressed to form a sheet, has been specially developed. 1977-
Publication No. 11229, Japanese Unexamined Patent Publication No. 117661, Japanese Unexamined Patent Publication No. 117661, Japanese Unexamined Patent Publication No. 117661
It is disclosed in Publication No. 62-208906, etc. All of the methods disclosed in these documents only describe a dry blending method for a two-component system of a fibrous filler and a matrix resin powder, and do not describe a method for simultaneously mixing a third or fourth component or more. [Problems to be Solved by the Invention] Powder (plant powder) produced during the polymerization stage of polymers is usually used as the matrix resin. However, this plant powder is uncolored, and in order to color the product sheet, colored pellets must be crushed and used, making it expensive. Furthermore, plant powder is a freshly polymerized polymer and does not contain various stabilizers such as heat stabilizers and ultraviolet absorbers. Therefore, there was a problem that long-term performance was low and deterioration occurred during processing. Furthermore, in order to improve the interfacial adhesion between the fibrous filler and the matrix resin, there was a problem in that very expensive modified resin powder had to be used. [Means for Solving the Problems] The present invention has been made to solve these problems, and includes a method for manufacturing a plastic sheet by mixing a matrix resin and a fibrous filler with an additive. The average particle size of the additive is equal to or smaller than the average particle size of the matrix resin, and the charging polarity of the additive when mixed is the same as that of the matrix resin and different from that of the fibrous filler,
The additive is also characterized by being adjusted or selected so that the amount of charge per unit weight of the additive is equal to or greater than that of the matrix resin. If the additive does not contain a thermoplastic resin as a binder, the additive is added to the matrix resin.
Mix 0.01 to 1 part by weight per 100 parts by weight, while
If the additive does not contain a thermoplastic resin as a main component or binder, the additive may be added to the matrix resin.
This object has been achieved by a method for producing a plastic sheet in which a fibrous filler is dispersed, which is further characterized in that 1 to 400 parts by weight are mixed per 100 parts by weight. The matrix resin may be any thermoplastic resin, and its type is not particularly limited, but examples include polyethylene resin, polypropylene resin, ethylene-propylene copolymer resin, ethylene-vinyl acetate copolymer resin, and ethylene-acrylic acid ester. Copolymer resin, polyethylene terephthalate resin, polystyrene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polycarbonate resin,
These include polyamide resin, polyacetal resin, methacrylic resin, and blend resins containing these.
The matrix resin is mixed in the form of powder or granules, and the particle size is often about 0.01 to 5 mm, particularly about 0.05 to 1 mm. Fibrous fillers include glass fibers, carbon fibers, metal fibers, asbestos, synthetic fibers such as aramid fibers, pulp, cotton, and the like. The amount of the fibrous filler to be mixed is usually about 1 to 400 parts by weight, particularly about 5 to 200 parts by weight, per 100 parts by weight of the matrix resin. The additive is a powder or granule at room temperature, the average particle size is equal to or smaller than the average particle size of the matrix resin, and when mixed with the matrix resin and fibrous filler, the charge polarity is the same as that of the matrix resin and the fibrous The filler is of a different type and has a charge amount per unit weight equal to or greater than that of the matrix resin. The average particle size of the additive is desirably smaller than the average particle size of the matrix resin, preferably 1/2 or less, preferably 1/3 or less, particularly 1/5 or less. In addition, the average particle diameter of the additive is 0.5 mmφ or less in absolute value, especially 0.1 mm.
Preferably, the diameter is less than or equal to φ. The smaller the particle size, the greater the number of powders, ie the surface area, for the same amount added, and the greater the effect. In the method of the present invention, additives that meet the above conditions are selected or adjusted to meet the above conditions. The average particle size may be adjusted by known means such as pulverization.
The charge polarity and the charge amount per unit weight can be adjusted by appropriately adding a positive charge control agent and a negative charge control agent. The amount of charge per unit weight can also be adjusted by other means. The amount of charge can be measured with a blow-off powder charge amount measuring device. To measure the amount of charge using a blow-off powder charge amount measuring device, the powder to be measured and a metal powder with a larger particle size are uniformly mixed at a weight ratio of 5:95, and the powder is sufficiently charged. let Weigh out approximately 200 mg of this mixture and place it in a Faraday cage.
Blow N ₂ gas at a pressure of 1 Kg/cm ² and discharge only the measured powder through the mesh. The amount of charge on the metal powder remaining in the cage is measured with an electrometer, and the amount of charge on the discharged powder is determined as the amount of charge ([μC/g], but the polarity is reversed). It is sufficient that the charge amount of the additive per unit weight measured in this manner is equal to or larger than the charge amount of the matrix resin, but it is preferably at least twice as much, particularly five times or more. The polarity is different,
If the amount of charge is small, the mixture after dry blending will not adhere electrostatically and will separate. Such additives used in the method of the invention fall into two groups. One of them is one that does not substantially contain thermoplastic resin as a binder of additives, and when mixing additives of this group, the mixing amount is about 0.01 to 1 part by weight, especially 0.01 to 1 part by weight, per 100 weight of matrix resin. Approximately 0.05 part by weight is appropriate. Less than 0.01 part by weight, coloring,
There is almost no effect of modification. On the other hand, if the amount exceeds 1 part by weight, the additive powder will cover the fiber surface, significantly impairing the adhesion between the matrix resin and the fibers, and significantly reducing the physical properties of the composite material. The other type contains a thermoplastic resin as a main component or as a binder. The thermoplastic resin is preferably one that is compatible with the matrix resin and can be uniformly mixed with the matrix resin by thermal melting. The content of the thermoplastic resin may be about 5 to 95% by weight. When mixing this group of additives, the mixing amount is 1 to 400 parts by weight per 100 parts by weight of matrix resin.
About 5 to 200 parts by weight is appropriate. If it is less than 1 part by weight or more than 400 parts by weight, the same problems as above will occur. Each group of additives may be a combination of two or more additives, and
These two groups of additives may be mixed in combination. These additives may be selected from known additives added to plastics that meet the above conditions. At that time, it goes without saying that processing such as pulverization may be performed as necessary. Examples of additives include various dyes, pigments, stabilizers, antioxidants, ultraviolet absorbers, plasticizers, charge control agents, modified resins with increased adhesive properties, and the like. On the other hand, since the method of the present invention utilizes adhesion due to charging, antistatic agents and the like are often undesirable. This additive is not electrically conductive like carbon black, but is an insulator that generally retains an electrical charge for a certain period of time. By adding the modified resin described above, the interfacial adhesion between the fibrous filler and the matrix resin can be improved. This modified resin is preferably one that has good compatibility with the matrix resin, and a modified resin that is the same resin as the matrix resin is particularly preferred. The modified resin belongs to the above-mentioned second group, and therefore, the appropriate mixing amount is 1 to 400 parts by weight per 100 parts by weight of the matrix resin. The order of mixing the matrix resin, fibrous filler, and additives is not critical, and any of them may be mixed first, but it is convenient to dry blend the three at the same time. Any known mixer may be used, such as a dry blender, V-type blender, ribbon blender, cone mixer, Henschel mixer, etc. After dry blending, the mixture may be pelletized and then a plastic sheet may be produced at a predetermined location, or the mixture may be directly heated and pressurized to produce a plastic sheet. [Function] Even if static electricity adhesion occurs between the two components in conventional dry blending of matrix resin and fibers, the static electricity phenomenon is suppressed by adding other components such as the third and fourth components. In some cases, the appearance was completely different, the adhesion stopped, and the physical properties deteriorated. The present inventors have elucidated this phenomenon and found that the substances added as the third and fourth components have the same polarity as the matrix resin powder, and therefore have the opposite polarity to the fibrous filler, and the amount of charge per average weight of the matrix resin powder is the same as that of the matrix resin powder. If it has greater chargeability than powder,
It has been found that this mixing system adheres electrostatically even after dry blending and can easily produce a homogeneous plastic sheet. Where the polarity of the additive is the same as that of the matrix, the additive serves to promote electrostatic adhesion between the matrix and the fibers, but where the polarity is opposite, the additive serves to promote separation. Figure 1 schematically shows the adhesion state after dry blending the matrix resin powder, fibrous filler, and additives using the method of the present invention, and Figure 2 schematically shows the state after dry blending the matrix resin powder, fibrous filler, and additives using the conventional method. show. In the condition of FIG. 1, the matrix and additive are negatively charged and the filler is positively charged, and the additive serves to attach the matrix and filler. On the other hand, in the state shown in Figure 2, the matrix and filler are negatively charged and the additive is positively charged.
The additive serves to separate the matrix and filler. [Example] Examples 1 to 4 Commercially available polypropylene plant powder (particle size
135g of commercially available chopped glass fiber (fiber diameter 11μm, length 13mm, Fuji Fiberglass "FES-13-1250") ) 90g in Table 1
Or dry blended with the additives listed in Table 2. The mixing machine uses a Henschel type mixer (Mitsui Miike Kakoki ``FM-10B''), and after inputting the materials,
Mixed for 30 seconds at a rotation speed of 1900 rpm. The rotating blade is
I used ZOSO. The amount of charge of the additive powder and the matrix powder was measured in a conventional manner using a blow-off powder charge amount measuring device TB-200 manufactured by Toshiba Chemical. SUS particles of 100 to 145 meshes were used for measurements. As a result, the amount of charge on the matrix resin powder was -1.5
[μC/g], and the charge amount of the additive was as shown in Table 1. Further, the adhesion rate of the mixture was evaluated by sieving the flocculent mixture to remove the matrix powder that was not electrostatically adhered, and then evaluating the weight % of the adhering matrix. An adhesion rate of 80% or more was considered "adhesion," and an adhesion rate of 80% or less was considered "separation." The strength and physical properties of the plastic sheet were evaluated as follows. Place the cotton mixture on two steel plates (2mm thick) with a spacer of 4 x 160 x 160mm (inner dimensions).
After putting scissors inside and heating at 200℃ for 3 minutes in a hot press, apply a pressure of 10Kg/cm ² to form a sheet.
A test piece sheet was prepared by cooling in a cold press at 20° C. under a pressure of 10 kg/cm ² for 4 minutes. Tensile strength (TS) and Izot impact strength were determined from this sheet.

【table】

[Table] The effect of additives (thermal stabilizers) was evaluated by the oxidation onset temperature (DSC measurement in air) ΔT compared to the case without additives. There is no effect if the amount added is less than 0.01 part,
If it is less than 1.0 parts, the strength and physical properties of the plastic sheet will be significantly reduced. Examples 5 to 7 The following colorants were used. Add 90 parts of polypropylene, 10 parts of pigment (titanium oxide and carbon black), a positive charge control agent ("BONTRON N-01" manufactured by Orient Chemical Industry Co., Ltd.) and a negative charge control agent ("BONTRON S-34" manufactured by Orient Chemical Industry Co., Ltd.) as appropriate. The mixture was kneaded in a axial extruder and freeze-pulverized to produce a coloring agent consisting of powder with a particle size of approximately 75 μm. This powder is
It had a structure in which the pigment was wrapped in a thermoplastic resin. The amount of charge of this powder was varied by appropriately adding positive and negative charge control agents. 13.5 times this colorant was mixed with 121.5 parts of the same commercially available polypropylene plant powder ("J900P") used in Examples 1 to 4, and 90 parts of commercially available chopped glass fiber strands ("FES-13-1250"). % and mixed under the same conditions as Examples 1 to 4. The adhesion rate of matrix resin powder after dry blending is shown in Table 3 below.

[Table] If the polarity of the colorant is the same as that of the matrix resin powder and the amount of charge is greater than that of the matrix, the mixed system will adhere. Example 8 When 0.05 part of a negative charge control agent ("BONTORON E-84" manufactured by Orient Chemical Industry Co., Ltd.) was directly added to the composition of Comparative Example 5 and dry blended, the adhesion rate of matrix powder was significantly improved to 95%. . At this time, the charge amount of the mixture of colorant powder and negative charge control agent was -20 [μC/g]. From this, it can be seen that when a plurality of additives are added in addition to the matrix powder, the total charge amount of the additive mixture should have the same polarity as the matrix powder and a larger value. Examples 9 to 12 The same polypropylene plant powder (“J900P”) as in Examples 1 to 4 and adhesive modified polypropylene resin powder (“QE050” manufactured by Mitsui Petrochemicals, average particle size 75μ)
m) was dry blended with 90 g of glass fiber ("FES-13-1250") in the composition shown in Table 4 below.
The mixing conditions were the same as in Examples 1-4. As a result, the amount of charge on the modified polypropylene was -6.5 [μC/
g]. All cotton-like mixtures after dry blending had 90% or more of the matrix powder adhered to them, and the modified polypropylene powder with small particle size was also uniformly adhered to the fiber surface. This mixture was formed into a sheet by the same method as in Examples 1 to 4, and the tensile length and airtightness were measured. Table 4 shows the results.

〔Effect of the invention〕

By the manufacturing method of the present invention, fiber-reinforced plastic sheets can be colored, modified, etc. at low cost without deteriorating their physical properties. It is also possible to improve the interfacial adhesion between the fiber and the matrix.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the state of adhesion of matrix resin and additives obtained by mixing according to the method of the present invention to a fibrous filler.
FIG. 2 is a diagram schematically showing the state of adhesion to a fibrous filler when mixed by a conventional method. 1... Matrix resin, 2... Fibrous filler, 3... Additive.

Claims (1)

[Claims] 1. A method for producing a plastic sheet by mixing a matrix resin, a fibrous filler, and an additive that does not contain a thermoplastic resin as a binder, wherein the average particle diameter of the additive is equal to or smaller than the average particle diameter of the matrix resin. The particle size is equal to or smaller than the particle size, the charge polarity when mixed is the same as that of the matrix resin and different from that of the fibrous filler, and the amount of charge per unit weight of the additive is equal to that of the matrix resin. or adjusted or selected to be larger, and the additive is added to 100 parts by weight of matrix resin.
A method for producing a plastic sheet in which a fibrous filler is dispersed, characterized by mixing 0.01 to 1 part by weight. 2. In a method of manufacturing a plastic sheet by mixing a matrix resin, a fibrous filler, and an additive containing a thermoplastic resin as a main component or binder, the average particle size of the additive is equal to the average particle size of the matrix resin. or smaller, the charge polarity when mixed with the additive is the same as that of the matrix resin and different from that of the fibrous filler, and the amount of charge per unit weight of the additive is equal to or greater than that of the matrix resin. 1. A method for producing a plastic sheet in which fibrous filler is dispersed, characterized in that 1 to 400 parts by weight of the additives are mixed with 100 parts by weight of a matrix resin.