JP2003183411A - Glass master batch pellet and molded article made from the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a GMB (glass master batch) with superior productivity which less makes a bridge at a hopper or the like when a blend of the GMB and a thermoplastic resin as a dilution resin is injection-molded, is improved in moldability and does not cause twist nor warp on the molded article. <P>SOLUTION: The GMB pellet comprises glass fibers with approximately same length as a pellet substantially arranged in the longitudinal direction of the pellet and is characterized by that the GMB pellet has a glass fiber content of 25-50 vol.%, a diameter D of 1.0-2.0 mm, a length L of 3-12 mm and a D/L of 0.04-0.40. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a glass fiber reinforced thermoplastic resin pellet having a relatively high glass fiber content, which is diluted with a virgin resin and used for injection molding.

[0002]

2. Description of the Related Art Conventionally, glass fiber reinforced thermoplastic resin pellets are known, in which a thermoplastic resin is melt-impregnated into a glass fiber as a matrix resin while pulling out continuous glass fibers and cut into a suitable length. . The glass fiber reinforced thermoplastic resin pellets, because the reinforced glass fibers present in the pellets are present in a long state,
By molding the pellets by injection molding or the like, a high-strength molded product can be obtained. For such glass fiber reinforced thermoplastic resin pellets, by increasing or decreasing the viscosity of the matrix resin to be melt-impregnated, the matrix resin impregnability is improved and the mechanical strength of the molded product is improved. It is known that

For example, in JP-A-6-246740, the glass fiber content is 3 to 67 vol%, the pellet length is 3 to 8 mm, and the pellet diameter is 1.7 to 5 mm. Glass fiber reinforced thermoplastic resin pellets having a ratio of 1.4 to 1.66 are known. Further, in JP-A-11-291241, by using a pellet having an average diameter of 1 mm or less and a length of 3 to 100 mm for injection molding, the pellet has flexibility and the residual glass fiber at the time of injection molding. It is known to remain long.

Furthermore, in recent years, the glass fiber reinforced thermoplastic resin pellets have a high glass fiber content, and this is used as a glass masterbatch (hereinafter, referred to as GMB), and other virgin resin is added to the glass masterbatch for use. Since it is possible to obtain molded products with high strength and at low cost, the above-mentioned GM
B is adopted as a molding material.

[0005]

However, when the glass fiber reinforced thermoplastic resin pellets having the above high glass fiber content are used as GMB, when mixed with virgin resin due to the large amount of glass fibers, There is a problem that the glass fiber is not uniformly dispersed in the molded product during injection molding because the glass fiber-rich portion is mixed with the virgin resin without the glass fiber. This decrease in the dispersibility of the glass fibers causes twists and warps in the molded product, and the twists and warps tend to occur particularly in molded products having a thin wall thickness.

Therefore, the GM described in the above-mentioned JP-A No. 11-291241, which uses thinner glass fibers, is used.
By using B, the residual fiber length of the glass fiber in the molded product remains long and GMB having a high glass fiber content is easily dispersed uniformly in the diluted resin, so that a molded product having high strength can be obtained. In order to produce GMB, the diameter of the glass fiber is small, so that the shape of the glass fiber is restricted, and the production amount per one time is low and the production efficiency is inferior as compared with the case of producing GMB having a large diameter. In addition, since the GMB is a long GMB that is longer than its diameter and may be entangled with each other, the GMB may be entangled in the hopper of the injection molding machine.
Sometimes caused a bridge.

Therefore, an object of the present invention is to provide a GMB having excellent productivity, and when GMB and a thermoplastic resin which is a diluting resin are mixed and injection-molded, a bridge does not occur in a hopper or the like, and molding is performed. Another object of the present invention is to provide a GMB which has excellent properties and does not cause twist or warp in the obtained molded product, and a molded product using the same.

[0008]

In order to solve the above problems, the present invention is a pellet comprising glass fibers and a thermoplastic resin, and glass fibers having substantially the same length as the pellets are substantially formed in the longitudinal direction of the pellets. In a glass masterbatch (GMB) pellets arranged in a regular manner, the glass fiber content of the GMB pellets is 25 to 50 vol%,
The diameter D of the GMB pellet is 1.0 to 2.0 mm,
The length L is 3 to 12 mm and the D / L is 0.04 to 0.
GMB pellets characterized in that they are 40.

The glass fiber in the GMB pellets has a diameter of 9 to 17 μm; the thermoplastic resin is a polypropylene resin or a grafted polypropylene resin; and the polypropylene resin or the grafted polypropylene resin has a melt flow rate. Thirty
It is preferably about 200 g / 10 minutes.

Further, the present invention is characterized by comprising any one of the above GMB pellets and a pellet-like or powder-like diluted resin made of a resin substantially the same as the resin constituting the GMB pellets. A glass fiber reinforced, characterized in that any one of the above GMB pellets is mixed and kneaded with a diluting resin consisting of a resin that is substantially the same as the resin constituting the GMB pellets, and injection molding is performed. Provided is a method for manufacturing a thermoplastic resin molded product.

Further, the present invention is a glass fiber reinforced thermoplastic resin molded article obtained by any one of the above GMB pellets and a resin which is substantially the same as the resin constituting the GMB pellets, Glass fiber content is 1.
A glass fiber reinforced thermoplastic resin molded article, which is 8 to 20.0 vol% and has an average wall thickness of 3 mm or less; and the above glass fiber reinforced thermoplastic resin molded article which is a tray.

According to the present invention described above, when GMB pellets are combined with a thermoplastic resin and molded, the resulting molded article has excellent dispersibility of glass fibers and is free from kinking and warping.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the following preferred embodiments. The GMB pellets of the present invention are obtained by aligning glass fibers in one direction and melt-impregnating or coating a thermoplastic resin in the glass fibers, and the glass fibers have substantially the same length as the pellets and are made of glass. A GMB pellet in which the fibers are arranged substantially in the longitudinal direction of the pellet.

The diameter of the glass fiber used in the GMB pellet of the present invention is not particularly limited, but is preferably 9 to 17 μm. When the glass fiber diameter is less than 9 μm, the surface area of the glass fiber becomes large when the glass fiber content is the same. On the other hand, when the glass fiber diameter exceeds 17 μm, the mechanical properties of the obtained molded product are poor. Not preferable.

The glass fiber content in the GMB pellets of the present invention is 25 to 50 vol% and is 25 to 45 vol.
% Is more preferable. If the glass fiber content is less than 25 vol%, the merit as a GMB is weak, while the glass fiber content is 50 vol%.
When it exceeds%, the dispersibility of the glass fiber in the molded product is poor, which is not preferable.

The thermoplastic resin used for the GMB pellets of the present invention is not particularly limited, and various commercially available resins can be used. For example, polyolefin resin, polyamide resin, polyester resin, polycarbonate resin, polyphenylene sulfide resin, polystyrene resin, etc. may be mentioned.

From the viewpoint of impregnating ability with respect to glass fiber, cost, and physical properties, polyolefin resin, polyamide resin, and polyester resin are preferable in the present invention.
Examples of the polyolefin resin include polypropylene and polyethylene; examples of the polyamide resin include nylon 6,6, nylon 6, nylon 12, and M.
XD nylon and the like; polyester-based resins include, for example, polyethylene terephthalate and polybutylene terephthalate, and it is particularly preferable in the present invention to use these resins. These resins may be mixed with additives such as colorants, modifiers, antioxidants and UV resistant agents, and fillers such as calcium carbonate, talc and mica.

Among the thermoplastic resins, it is preferable to use a polypropylene resin or a grafted polypropylene resin from the viewpoint of cost performance of the molded product. The polypropylene resin or the grafted polypropylene resin has a melt flow rate of 30 to 200 g /
It is preferably 10 minutes, and further 60 to 150 g /
More preferably, it is 10 minutes. When the melt flow rate is less than 30 g / 10 minutes, the impregnability and dispersibility of the resin into the glass fiber may be poor, while when the melt flow rate exceeds 200 g / 10 minutes, the resin has a low molecular weight. Therefore, the mechanical properties of the obtained molded product may be inferior, which is not preferable.

The polypropylene resin may be a general-purpose polypropylene resin, and the grafted polypropylene resin is
It can be obtained by a method of graft-polymerizing a polymerizable unsaturated carboxylic acid compound or its derivative on a polypropylene resin. Examples of the unsaturated carboxylic acid used for carboxylic acid modification include maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid and the like.
The unsaturated carboxylic acid derivatives include acid anhydrides, esters, amides, imides, and metal salts thereof.
Specific examples thereof include maleic anhydride, itaconic anhydride, methyl acrylate, ethyl acrylate, butyl acrylate, glycidyl acrylate, methyl methacrylate,
Ethyl methacrylate, glycidyl methacrylate, maleic acid monoethyl ester, maleic acid diethyl ester, fumaric acid monomethyl ester, fumaric acid dimethyl ester, acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, fumaric acid monoamide, maleimide, N- Butyl maleimide, sodium methacrylate, etc. can be mentioned.

Of the above unsaturated carboxylic acid compounds and derivatives thereof, glycidyl esters of acrylic acid and methacrylic acid and maleic anhydride are preferred, and the grafted polypropylene resin is 0.1 to 4 parts thereof.
0% by mass is preferably a graft chain composed of the unsaturated carboxylic acid compound or its derivative as described above,
It is particularly preferable that the content of these graft chains is 0.1 to 10% by mass.

In the method for producing the GMB pellets of the present invention, the glass fiber strands obtained by bundling glass fibers are fed into a molten resin impregnation tank, and the glass fiber strands are impregnated with the resin by the melt impregnation method, and then 1 A method is preferred in which one or more glass fiber strands are drawn out by one nozzle and then cut to obtain GMB pellets.

The length of the GMB pellet of the present invention is 3-1.
It is necessary to be 2 mm, and more preferably 6 to 10 mm. When the GMB pellet length is less than 3 mm, pellet breakage when cutting the impregnated product after melt impregnation with the matrix resin and residual glass fiber in the molded product are short, resulting in poor mechanical properties of the molded product. Not preferred because of On the other hand, the cut length of the melt-impregnated material is 12 m
When it exceeds m, when the GMB pellets are put into an ordinary molding machine, the GMB pellets easily form a bridge and the handling property is poor, and the fluidity at the time of molding is poor, so that the glass fiber Dispersibility is poor, and twisting and warpage of the molded product occur, which is not preferable. The GMB pellets of the present invention are obtained by impregnating continuous glass fiber strands with a thermoplastic resin and cutting the strands.
The length of glass fibers in the pellet is approximately equal to the length of GMB pellet.

The diameter of the GMB pellet of the present invention is 1.0 to
It is important to be 2.0 mm, 1.0 to 1.7 m
More preferably m. If the diameter of the GMB pellets is less than 1.0 mm, the productivity of the GMB pellets is poor, which is not preferable. On the other hand, if the diameter of the GMB pellets exceeds 2.0 mm, a diluent resin is added to dilute the GMB pellets to form the pellets. In such a case, the dispersibility of the glass fiber in the obtained molded product is poor, and the molded product is twisted or warped, which is not preferable.

Furthermore, it is important that the D / L is 0.04 to 0.40, where D is the diameter and L is the length of the GMB pellets of the present invention. It is more preferably 0.30. By making the length and diameter a specific ratio, the GMB pellets are excellent in dispersibility at the time of blending the GMB pellets and the diluted resin, and the melting and dispersion of the GMB pellets proceeds in the molding machine. Excellent dispersibility of the glass fibers, reducing twist and warpage in the molded product.

The method for producing a molded product using the GMB pellets of the present invention is a method in which a diluted resin is added to the GMB pellets and injection molding is carried out. The molded product has a desired shape and strength and is less likely to be twisted or warped. Can be obtained. The injection molding method and the injection molding device may be conventionally known methods and devices.

The diluting resin (virgin resin) refers to a thermoplastic resin simple substance that does not substantially contain glass fiber that is usually used, and the same thermoplastic resin as that mentioned above as the constituent resin of the GMB pellets is used. Can, GMB
It is preferable to use a resin that is substantially the same as the resin that constitutes the pellet. The substantially same type of resin means that the main skeletons of the resins are the same type, for example, a polypropylene resin and a grafted polypropylene resin, and in this case, the grafted polypropylene resin is used as the matrix resin of the GMB pellets. It is possible to use polypropylene resin as the diluting resin. The amount of the diluting resin used can be appropriately selected depending on the strength of the desired molded product, but it is preferable to adjust it so that the glass fiber content of the molded product is 1.8 to 20.0 vol%.

The blend of the present invention can be obtained by mixing the GMB pellets and the diluted resin. The glass fiber concentration in the blend was 1.
It is preferable to adjust it so as to be 8 to 20.0 vol%. The method of blending may be a conventionally known method. A molded article obtained by injection molding the blend is
The dispersibility of the glass fiber is good and there is no twist or warp. The average wall thickness of the molded product is preferably 3 mm or less. There are various molded products having an average wall thickness of 3 mm or less, but when the molded product is used as a tray, there is no warp or twist, and when the molded product is placed on a flat plate, the molded product is not deformed. Without confirmation, there is no rattling, and it is possible to stack well even if the trays are stacked.

[0028]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. (Example 1) Four glass fiber strands in which 600 glass fibers each having a diameter of 13 μm are bundled are aligned, and the above glass is placed in an impregnation bath in which a grafted polypropylene resin having a melt flow rate of 120 g / 10 min is melted at 260 ° C. The fiber strand is drawn out from a nozzle having a diameter of 1.3 mm, cooled, and then cut into a length of 10 mm to have a diameter (D) of 1.3.
mm, length (L) 10 mm, D / L = 0.13, glass fiber content 35 vol% GMB pellets of the present invention were obtained. This GMB pellet was blended with the color master batch and the diluted polypropylene resin to obtain a blended product such that the glass fiber content in the molded product was 8.5 vol%. The above grafted polypropylene resin is a polypropylene resin in which maleic anhydride is 0.24 parts by mass in Grat polymerization per 100 parts by mass of the polypropylene resin.

The blend thus obtained was put into an injection molding machine to mold a tray having a size of 400 mm × 500 mm and a thickness of 2.5 mm. At this time, the bridge of the blend did not occur in the hopper of the molding machine. The gate position of the mold of the molding machine was the central one-point gate. When the obtained molded product was placed on a flat plate surface, there was no rattling and no distortion, twist or warp was observed.

(Comparative Example 1) 6 glass fibers having a diameter of 13 μm were used.
15 pieces of glass fiber strands bundled with 00 pieces were aligned, and the glass fiber strands having a diameter of 2 were prepared in an impregnation bath in which a grafted polypropylene resin (same as in Example 1) having a melt flow rate of 120 g / 10 min was melted at 260 ° C. After pulling out from the nozzle of 0.5mm, after cooling, length 10
Cut to mm, diameter (D) 2.5 mm, length (L) 1
0 mm, D / L = 0.25, glass fiber content 35vo
1% of GMB pellets of the comparative example were obtained. The obtained GMB
A pellet and a blend were prepared in the same manner as in Example 1, and injection-molded in the same manner to obtain a molded tray product. At this time, the bridge of the blend did not occur in the hopper of the molding machine. Furthermore, when the molded product obtained in the same manner as in Example 1 was placed on a flat plate surface, there was twisting, and the protrusion of the corner portion of the molded product was observed from the plate surface.

(Examples 2 to 5 and Comparative Examples 2 to 5) Molded articles were obtained in the same manner as in Example 1 except that the various conditions in Example 1 were changed as shown in Table 1 below. When the occurrence of bridges in the hopper of the blended product and the deformation of the molded product at this time were examined, the results shown in Table 2 below were obtained.

[0032] The productivity of Examples 1, 3, 4, 5, and Comparative Examples 1 and 3 was good, but that of Comparative Example 2 was poor.

[0033] A: Excellent. ◯: Good. X: Bad.

[0034]

EFFECTS OF THE INVENTION According to the present invention as described above, when GMB and a thermoplastic resin are mixed and injection-molded, a bridge is not generated in a hopper and the like, and the moldability is excellent.
It is possible to provide GMB with high productivity, in which the obtained molded product does not cause twisting or warpage.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 23/10 C08L 23/10 51/06 51/06 101/00 101/00 // B29K 105: 12 B29K 105: 12 309: 08 309: 08 F-term (reference) 4F070 AA15 AB08 AB24 AC28 AC75 AD02 AE01 FA04 FB03 FB04 4F072 AA02 AA08 AB09 AD04 AD52 AD53 AD54 AG05 AJ04 AK15 4F201 AA11 AA11F AB11 AB25 AD04 AR12 BA04 BC42 BC19 BC29 BC42 BL19 BC29 AA11 AB11 AB16 AC01 AH58 JA07 JE16 JF01 JF21 JL02 JM01 JN01 4J002 BB121 BB211 BN051 CF061 CF071 CL011 CL031 DL006 FA046 FD016

Claims (8)

[Claims] 1. A glass masterbatch pellet comprising glass fibers and a thermoplastic resin, wherein glass fibers having substantially the same length as the pellets are substantially arranged in the longitudinal direction of the pellets. The glass fiber content is 25 to 50 vol% and the diameter D of the glass masterbatch pellets is 1.0 to
2.0 mm, the length L is 3 to 12 mm, and D /
A glass masterbatch pellet, wherein L is 0.04 to 0.40. 2. The glass masterbatch pellet according to claim 1, wherein the glass fiber has a diameter of 9 to 17 μm. 3. The thermoplastic resin is a polypropylene resin or a grafted polypropylene resin.
Or the glass masterbatch pellet according to 2. 4. The polypropylene resin or grafted polypropylene resin has a melt flow rate of 30 to 2
The glass masterbatch pellet according to claim 3, which is 00 g / 10 minutes. 5. A pellet or powder form comprising the glass masterbatch pellet according to any one of claims 1 to 4, and a resin substantially the same as the resin constituting the glass masterbatch pellet. And a diluted resin of 1. 6. The glass masterbatch pellet according to claim 1, and a diluting resin which is substantially the same resin as the resin constituting the glass masterbatch pellet is mixed and kneaded. And a method of manufacturing a glass fiber reinforced thermoplastic resin molded article, characterized by performing injection molding. 7. A glass fiber reinforced heat obtained by the glass masterbatch pellets according to claim 1 and a resin which is substantially the same as the resin constituting the glass masterbatch pellets. A plastic resin molded product having a glass fiber content of 1.8 to 20.0 vo
A glass fiber reinforced thermoplastic resin molded article, which is 1% and has an average wall thickness of 3 mm or less. 8. The glass fiber reinforced thermoplastic resin molded article according to claim 7, which is a tray.