JP2001123011A - Method for producing resin molded article containing fine hollow glass spheres - Google Patents

Abstract

(57) [Summary] A resin molded article having a small fracture rate of a minute hollow glass spherical body, a large strength of the molded article, and excellent in weight reduction, low dielectric constant, and low dielectric loss tangent is obtained. The average particle size is 0.1 to 30 μm, and the particle size is 0.1.
A heat-meltable resin composition containing fine hollow glass spheres having 90 to 30% by weight or more of particles having a particle size of 30 to 30 μm and an apparent density of 0.1 to 0.8 g / cm ³ is obtained by melting the resin at a melting temperature of Melt molding is performed at the above temperature and at a pressure of 200 MPa or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a resin molded article containing fine hollow glass spheres.

[0002]

2. Description of the Related Art In recent years, it has been required to reduce the weight of resins used in many fields. For example, when used for electric wires, it is desired to reduce the weight of the coating resin and the connector resin in consideration of the load during transportation and use, and also for interior and exterior parts for vehicles such as automobiles, It is desired to reduce the weight of resin as a part of reducing fuel consumption and cost.

[0003] On the other hand, in the era of the advanced information society, communication devices such as satellite broadcasts and mobile phones have tended to be digitized and processed at high speed, and accordingly, wiring wires and wires used for these devices have been developed. For a LAN cable, a cable connector, or a member such as a resin or plastics around the LAN cable or the cable connector, a low dielectric constant and a low dielectric loss tangent are desired.

The weight reduction, low dielectric constant, and low dielectric loss tangent of the resin used for such members are generally achieved by introducing air and other inert gases into the resin. In this case, as a method for introducing air and other inert gas into the resin, addition of a chemical foaming gas foaming hollow substance and the like are known. JP-A-3-3218, JP-A-3-3219 and the like have proposed chemical foaming.
Although it is proposed in Japanese Patent Publication No. 09, there are difficulties such as the difficulty of forming closed cells depending on the use, the requirement of extremely strict temperature during molding, and the necessity of large-scale equipment. .

On the other hand, as one of the hollow materials having relatively high pressure resistance, a fine hollow glass sphere called a glass balloon is commercially available. The addition of the fine hollow glass spheres is proposed in Japanese Patent Application Laid-Open No. 1-168742. However, the addition of the fine hollow glass spheres in the resin is not preferable because the compression stress or the compression stress in the molding step such as injection molding of the resin. Since a frictional force is applied, as much as 20 to 80% of the spherical glass body is broken. As a method of reducing this destruction rate, it is conceivable to increase the thickness of the minute hollow glass sphere, but in this case, there is a disadvantage that the original purpose of weight reduction and low dielectric constant is impaired. .

As a technique for reducing the breaking rate of the minute hollow glass spheres described above, Japanese Patent Application Laid-Open No. 5-139783 discloses a method.
As disclosed in Japanese Patent Application Laid-Open Publication No. H11-260, it has been proposed to add a thermoplastic elastomer to a resin containing fine hollow glass spheres. However, in many cases, thermoplastic elastomers that can be used have poor compatibility with the resin, and when the molding temperature is high, the thermoplastic elastomer is deteriorated. . Further, there is also a problem that the strength of the resin molded article is considerably reduced by the addition of the minute hollow glass sphere.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a fine hollow glass sphere having a small fracture rate, a small limitation on the resin that can be used, and the strength of the molded body being not reduced by the inclusion of the fine hollow glass sphere. An object of the present invention is to provide a method for producing a glass molded article containing a glass sphere. Thereby, an object is to obtain a resin molded body excellent in weight reduction, low dielectric constant, and low dielectric loss tangent.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the present invention relates to a particle having an average particle diameter of 0.1 to 30 μm and a particle diameter of 0.1 to 30 μm. Is 90% by weight or more of the whole and the apparent density is 0.1 to 0.1%.
A heat-meltable resin composition containing a fine hollow glass sphere having a weight of 8 g / cm ³ was heated at a temperature not lower than the melting temperature of the resin,
A method for producing a resin molded article containing fine hollow glass spheres, characterized by molding at a pressure of 200 MPa or less.

The present inventors have studied the relationship between the particle size of hollow glass spheres and the fracture rate when molding a heat-fusible resin composition containing the fine hollow glass spheres having various particle sizes. Considered in detail. As a result, surprisingly, in the molding process of the resin, when the particle diameter and the apparent density of the micro hollow glass sphere have predetermined physical properties, under the predetermined molding conditions, the destruction rate is significantly reduced. I found it. Thereby, compared to the case where the hollow glass spherical body has a large particle diameter, under predetermined molding conditions, the strength of the molded body does not decrease even if the content in the resin is the same, and the resin molded body is It was confirmed that the weight was reduced, and at the same time, the dielectric constant and the dielectric loss tangent were reduced.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In the microscopic hollow glass sphere used in the present invention, the average particle diameter is important. Having an average particle size of 0.1 to 30 μm, and a particle size of 0.1 to 30 μm
It is necessary that m particles account for at least 90% by weight of the whole. If the average particle size is larger than 30 μm, the breaking rate will increase, and the object of the present invention will be lost. On the other hand, when the average particle size is smaller than 0.1 μm, the bulk becomes bulky, the handling property and the melt viscosity as a composition increase, and the moldability deteriorates. Especially, it turned out that the average particle diameter of the micro hollow glass sphere is preferably 0.1 to 20 μm.

Also, the apparent density of the minute hollow glass sphere is important. Apparent density of 0.1 to 0.8 g / c
m ³ . The apparent density is 0.8g / c
If it exceeds m ³ , it is difficult to reduce the weight and / or the dielectric constant of the object, and the object of the present invention is impaired. On the other hand, when the apparent density is less than 0.1 g / cm ³ , the spherical shell becomes too thin, and not only the yield at the time of production of the micro hollow glass spheres is greatly reduced, but also the resin composition containing the micro hollow glass spheres is reduced. The breaking rate of the minute hollow glass sphere at the time of molding also increases. In addition,
In the present invention, the apparent density refers to the weight (g / c) of the hollow glass spherical body per volume including the void portion of the hollow glass spherical body.
m ³ ).

The fine hollow glass sphere used in the present invention may be any one as long as it has the above-mentioned physical properties. Among them, glass having an average particle diameter of 3 μm or less is obtained by wet-pulverizing a glass preparation raw material containing a foaming agent. It is preferable that the slurry is formed by generating a slurry containing the prepared raw material particles, turning the slurry into droplets, and heating the droplets.

Examples of the glass constituting the minute hollow glass sphere include borosilicate glass, soda-lime glass, and zinc phosphate glass. Such a raw material for glass is vitrified by heating, and is prepared in such a ratio that a plurality of raw materials have a target glass composition. Glass raw materials include silica sand, soda ash, borax,
Boric acid, zinc white, lime, Ca ₃ (PO ₄ ) ₂ , Na ₄ P ₂ O ₇
Is exemplified. The glass blending raw material contains a foaming agent. Examples of the foaming agent include sodium, potassium, lithium, calcium, magnesium, barium, aluminum and zinc sulfates, carbonates, nitrates and acetates. The content of the foaming agent is preferably 0.05 to 20.0% by weight in terms of SO ₃ , NO ₂ or CO _{2 in} the glass mixture raw material.

[0014] The glass blending raw material is preferably wet pulverized. A fine hollow glass sphere having the above-mentioned properties can be advantageously produced by a wet method, not a dry method. The wet mill used is preferably a medium stirring mill represented by a ball mill or a bead mill, but may be another wet mill. Examples of the liquid used for wet pulverization include flammable liquids. Among them, fuel oils, especially kerosene and heavy oil, are easy to handle and have good thermal efficiency, and the glass blended raw material is uniformly heated and efficiently vitrified and foamed, so that it is suitable as the liquid constituting the slurry of the present invention. This liquid may include other liquids, for example, water.

When the average particle diameter of the glass-mixed raw material particles after the wet pulverization exceeds 3 μm, it is difficult to obtain fine hollow glass spheres having a uniform composition. Above all, the average particle diameter of the glass-mixed raw material particles after wet pulverization is more preferably in the range of 0.01 to 1 μm.

The slurry of the glass-mixed raw material particles after the wet pulverization is formed into droplets. The size of the droplet is preferably 1 to 100 μm. If the droplets are too large, combustion due to heating becomes unstable, while if too small, the glass composition of the resulting fine hollow glass spheres becomes non-uniform. Examples of the method for generating droplets include a method using spraying, a method using ultrasonic waves, a method using centrifugal force, and a method using static electricity, and a method using spraying is preferable in terms of productivity. The generated droplets are heated to melt the glass-mixed raw material and gasify the foaming component in the glass to form a fine hollow glass sphere. The spray pressure of the slurry is preferably 0.01 to 8 MPa.

As the heating means, combustion, electric heating or the like can be preferably used. The heating temperature depends on the vitrification temperature of the glass-mixed raw material and the residence time during heating, but is preferably 300 to 2000 ° C. It is preferable to use fuel oil as the liquid constituting the slurry because the fuel oil is used as part or all of the heating energy.

The fine hollow glass sphere obtained as described above is recovered by means such as a cyclone, a bag filter, a scrubber, and a packed tower. Next, it is preferable to remove the unfoamed product and the hollow glass spheres outside the range used in the present invention by using a flotation method using water or alcohol having a low specific gravity for the recovered product. Then the hollow glass sphere is
Classify using a wind classifier or sieving device,
A fine hollow glass sphere having a particle diameter used in the present invention is obtained.

The micro hollow glass sphere used in the present invention is
Surface treatment may be performed. The surface treating agent is not particularly limited, but preferable examples thereof include silane-based, titanium-based, aluminum-based, and zirconium-based agents.

As the resin used in the present invention, an inorganic or organic resin can be used as long as the resin can be melted by heat. For example,
General-purpose plastics, engineering plastics, super engineering plastics, and the like can be used. Preferred examples thereof include polyethylene resin, polypropylene resin, polystyrene resin, A
BS resin, AS resin, acrylic resin, vinyl chloride resin, various polyamide resins, polyoxymethylene resin, polycarbonate resin, modified polyphenylene ether resin, polyethylene terephthalate resin, polybutylene terephthalate resin, fluorine-containing resin, polysulfone resin, polyether sal Phone resin, polyphenylene sulfide resin, polyamideimide resin, polyetherimide resin, polyimide resin, liquid crystal resin, polyetheretherketone resin and the like.

Among the above resins, in the present invention, the MFR
It is preferable to use a resin having a value of 0.1 to 100 g / 10 minutes. When the MFR value is smaller than the above range , the breaking rate of the fine hollow glass sphere increases, while when the MFR value is large, instability of molding and entrainment of air during molding occur, which are both undesirable. . The MFR value is particularly 1 to
50 g / 10 min is preferred. Here, the MFR value is measured by a method according to the resin to be used, and is an amount (g) of the resin that passes through a nozzle having a diameter of 2 mm and a length of 10 mm at a predetermined temperature equal to or higher than the melting temperature under a predetermined load for 10 minutes. / 10 minutes)
Is defined as

Particularly preferred resin in the present invention is the above-mentioned MFR.
It is appropriate to use a fluororesin having a value. Examples of the fluorine-containing resin include copolymers of a fluoroolefin such as tetrafluoroethylene and chlorotrifluoroethylene with a fluorine-containing monomer such as perfluoro (alkyl vinyl ether), hexafluoropropylene, vinyl fluoride, and vinylidene fluoride. Is mentioned. Further, a copolymer of a fluoroolefin and an α-olefin containing no fluorine such as ethylene, propylene, and butene may also be used.

Specific examples of the preferred fluorine-containing resin as described above include a tetrafluoroethylene-hexafluoropropylene-based copolymer (hereinafter, also referred to as FEP) and a tetrafluoroethylene-perfluoro (alkyl vinyl ether) -based copolymer. And a copolymer (hereinafter, also referred to as PFA), a tetrafluoroethylene-ethylene-based copolymer, a tetrafluoroethylene-propylene-based copolymer, and the like. In particular, PFA, ETFE, and FEP are preferred.

The MFR value of PFA is ASTM D-33
07 at 372 ° C, 5Kg load for 10 minutes,
Amount passing through a nozzle having a diameter of 2 mm and a length of 10 mm (g / 1
0 minutes). The MFR value of FEP is AS
As the same throughput at 372 ° C. and 5 kg load specified in TM D-2116, the MFR value of ETFE is 297 ° C., 5 kg specified in ASTM D-3159.
Each is defined as a similar throughput under a kg load.

The resin molded article containing the fine hollow glass spheres of the present invention is produced by molding the above-mentioned heat-meltable resin composition containing the fine hollow glass spheres. The content of the fine hollow glass spheres in the above composition varies depending on the required characteristics and the type of resin used, but is 1 to 50% by volume, especially 10 to 30% by volume, based on the composition containing the fine hollow glass spheres. % By volume is appropriate.

In the resin composition of the present invention, a fibrous reinforcing material, a filler, an additive, a stabilizer, and a flame retardant can be used alone or in combination thereof as long as the purpose is not impaired. Specifically, as a fibrous reinforcing material, carbon, potassium titanate, aluminum borate, calcium carbonate,
Inorganic fibers made of asbestos, silicon carbide, silicon nitride, calcium metasilicate and the like, and organic fibers such as aramid fibers. As a filler, titanium oxide, antimony trioxide, creel, hentonite, sericite, zeolite, gypsum, talc, mica, kaolin, graphite, carbon black, molybdenum disulfide, or zinc, aluminum, copper, magnesium, calcium It is possible to add metal powders such as iron and iron, and powders of oxides, carbonates or hydroxides thereof. Examples of the additives include brominated flame retardants, heat stabilizers, antioxidants, and ultraviolet absorbers.
In addition, the composition can be formed by blending a dispersant, a colorant, and the like.

The resin composition mixed with the minute hollow glass spheres is then melt-molded. In the present invention, the molding conditions are important together with the physical properties of the minute hollow glass spheres. That is, when the molding conditions are not favorable, even if the minute hollow glass sphere has the above-mentioned physical properties, the sphere is broken at the molding stage and the object cannot be achieved. Thus, it has been found that by performing such melt molding at a temperature equal to or higher than the melting temperature of the resin and at a pressure of 200 MPa or less, the minute hollow glass spheres contained in the resin composition are not broken. The melt molding temperature varies depending on the resin, but is preferably 200 to 450.
° C is adopted. In particular, a case where the temperature is 40 ° C. or more than the melting temperature is particularly appropriate.

The pressure varies depending on the type of the molded article and the molding method, but in any case, if it is within the above range, the minute hollow glass body in the resin composition is remarkably broken. In particular, it has been found that the pressure is suitably from 10 to 150 MPa.

The melt molding methods include injection molding, extrusion molding, compression molding, inflation molding, coating,
Examples include transfer molding using a mold and the like,
Preferably, injection molding, extrusion molding or compression molding can be employed.

In the molding, it is preferable to sufficiently mix the resin composition by melt mixing or the like. For example, a high-temperature kneader, a screw-type extrusion kneader, or the like can be used. In order to uniformly disperse the fine hollow glass spheres in the composition, a co-directional twin-screw extruder can also be used.

The molding may be carried out directly from the resin composition, but in some cases, extrusion molding or the like is preferable, and pellets having a diameter of 1 to 5 mm and a length of 1 to 10 mm are produced. The final molded product can be manufactured by extrusion molding, injection molding, transfer molding or compression molding. In this case, each molding condition needs to be performed under the above conditions.

[0032]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. In the following, Examples 1 to 4, Example 7, and Example 8 are examples, and Examples 5, 6, and 9 to 1 are examples.
4 is a comparative example.

Examples 1 to 6 17.5 g of silicon dioxide, 4.5 g of calcium carbonate, 7.8 g of boric acid, 1.0 g of dibasic calcium phosphate, 0.4 g of potassium carbonate, 0.4 g of sodium sulfate.
6 g, dispersant (Homogenol L-1820, manufactured by Kao Corporation)
1.6 g together with 150 g of kerosene were charged into a ball mill made of alumina and wet-pulverized at 100 rpm for 1 hour to obtain a slurry state.

Next, the slurry was sprayed with a two-fluid nozzle, and the flame was approached to ignite and spray combustion was performed to produce the slurry. The particle diameter and apparent density were adjusted by adjusting the slurry concentration and spray pressure in the slurry state. As a result, the apparent densities were all 0.5 g / cm ³ , and the average particle diameter (unit: μm) is shown in Table 1. Particles having a particle diameter of 0.1 to 30 μm were 93 wt. % Fine hollow glass spheres having a% by weight.

Next, with respect to 90 volume% of polybutylene terephthalate resin ("UBE PBT # 1000", trade name of Ube Industries, Ltd .; hereinafter, referred to as "PBT"), the fine hollow glass spheres having the above particle diameters are used. , And charged into a co-rotating twin-screw extruder with a kneading function set at a cylinder temperature of 280 ° C.
The strands kneaded and extruded at a rotational speed of rpm were cooled with water and then cut into pellets.

The obtained pellets were heated at a cylinder temperature of 280.
Into a hopper of an injection molding machine at 80 ° C. and a mold temperature of 80 ° C., and injection molded at a holding pressure of 80 MPa to produce a test piece. With respect to this test piece, the apparent density of the molded article was measured by the underwater displacement method, and the fracture rate of the minute hollow glass sphere in the molded article was calculated. Table 1 shows the results. As is evident from Table 1, as the average particle diameter became smaller, the breakage rate of the minute hollow glass sphere was significantly reduced.

[0037]

[Table 1] [Example 7] Tetrafluoroethylene-perfluoro (alkyl vinyl ether-based copolymer ("Aflon PFA P-
62X ". Asahi Glass Co., Ltd.) A resin composition of 60% by volume and 40% by volume of a minute hollow glass sphere was used. Examples 1 to 6
The hollow glass spheres manufactured in the same manner as described above have an average particle diameter of 10 μm and particles having a particle diameter of 0.1 to 30 μm as a whole 9 μm.
3% by weight and apparent density was 0.4 g / cm ³ . The above resin composition was heated at a cylinder temperature of 350 ° C. and a pressure of 100 MPa.
In a, pellets were produced by a co-directional twin screw extruder.

The pellets were heated at a cylinder temperature of 370 ° C.
Injection molding was performed at an injection pressure of 10 MPa, and test pieces (ASTM
D-6383 Dumbbell). The specific gravity and tensile breaking strength of the test piece were measured, and the results are shown in Table 2. Further, the pellets were weighed at 370 ° C. under a load of 0.5 MN in a 20 cm square.
After compression molding into a 1 mm thick sheet and aluminum deposition on both sides, the dielectric constant was measured. The results are shown in Table 2. The obtained composition was able to reduce the weight and dielectric constant of the matrix resin.

Example 8 60% by volume of a copolymer of tetrafluoroethylene and ethylene ("Neoflon FEP NP-20", trade name of Daikin Industries, Ltd.) and 40% by volume of fine hollow glass spheres as in Example 7 From the resin composition consisting of the following, pellets were produced in the same manner as in Example 7. The above pellets were put into a hopper, injection-molded at a cylinder temperature of 350 ° C. and an injection pressure of 10 MPa, and a test piece (ASTM D-6)
No. 383 dumbbell). The specific gravity of the test piece was measured, and the results are shown in Table 2. Further, the pellet is heated at 350 ° C.
After compression molding into a sheet of 20 cm square and 1 mm thickness under a load of 0.5 MN, aluminum was vapor-deposited on both sides, and the dielectric constant was measured. The results are shown in Table 2. The resulting composition is
The weight reduction and low dielectric constant of the matrix resin were realized.

[Example 9] A copolymer of tetrafluoroethylene and ethylene ("Aflon LM LM-740", trade name of Asahi Glass Co., Ltd.) was 60% by volume, and the same hollow glass sphere as in Example 7 was 40% by volume. Was injected into a hopper and injection-molded at a cylinder temperature of 350 ° C. and an injection pressure of 10 MPa to produce a test piece (ASTM D-6383 No. dumbbell).

The specific gravity of the test piece was measured, and the results are shown in Table 2. Further, the pellets are dried at 350 ° C. under a load of 0.5 MN for 2 minutes.
After compression molding into a sheet of 0 cm square and 1 mm thickness, aluminum was vapor-deposited on both sides, and the dielectric constant was measured. The results are shown in Table 2. The obtained composition was able to reduce the weight and dielectric constant of the matrix resin.

Example 10 A test piece of a resin molded product was produced in the same manner as in Example 7 except that a fine hollow glass sphere was not used. Table 2 shows the measurement results of the specific gravity, the dielectric constant, and the tensile strength at break of the test piece.

Example 11 A test piece of a resin molded product was produced in the same manner as in Example 8 except that a fine hollow glass sphere was not used. Table 2 shows the measurement results of the specific gravity and the dielectric constant of the test piece.

Example 12 A test piece of a resin molded product was produced in the same manner as in Example 9 except that a fine hollow glass sphere was not used. Table 2 shows the measurement results of the specific gravity and the dielectric constant of the test piece.

Example 13 A test piece of a resin molded product was produced in the same manner as in Example 7, except that the injection pressure at the time of injection molding of the pellet was 250 MPa. Table 2 shows the measurement results of the specific gravity and the tensile strength at break for the test pieces.

Example 14 A test piece of a resin molded product was produced in the same manner as in Example 9, except that the injection pressure at the time of injection molding of the pellet was 250 MPa. Table 2 shows the measurement results of the specific gravity of the test pieces.

[0047]

[Table 2]

[0048]

EFFECTS OF THE INVENTION A resin molded article containing fine hollow glass spheres, which has a small breaking rate of the fine hollow glass spheres, has a small restriction on the resin that can be used, and does not reduce the strength of the molded body due to the inclusion of the fine hollow glass spheres. A new manufacturing method is provided.

The obtained resin molded article is excellent in weight reduction, low dielectric constant and low dielectric loss tangent, and is extremely useful as an electric wire coating, a LAN cable, a plastic member or a part for or around a vehicle.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masao Unno 3-474-2 Tsukakoshi, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Within Asahi Glass Co., Ltd. (72) Inventor Kenshi Yamada 10 Goi Kaigan, Ichihara-shi, Chiba Prefecture Asahi Glass Co., Ltd. F term (reference) 4F071 AA15X AA23X AA27 AA45 AB28 AF53 AG28 AH11 AH12 BA01 BB03 BB04 BB05 BB06 BB09 BC01 BC07 4G062 AA14 BB01 BB05 CC04 CC08 MM15 4J002 AA011 BD151 BD161 CF071 DL006 FA106

Claims (6)

[Claims] (1) an average particle diameter of 0.1 to 30 μm and a particle diameter of 0.1
A heat-meltable resin composition containing minute hollow glass spheres having 90% by weight or more of particles having a particle size of 1 to 30 μm and an apparent density of 0.1 to 0.8 g / cm ³ was prepared by melting the resin at a melting temperature of the resin. A method for producing a resin molded article containing fine hollow glass spheres, which is melt-molded at the above temperature and at a pressure of 200 MPa or less. 2. The fine hollow glass spheres are wet-pulverized from a glass-forming raw material containing a foaming agent to produce a slurry containing glass-forming raw material particles having an average particle size of 3 μm or less. The manufacturing method according to claim 1, wherein the method is formed by heating a droplet. 3. The method according to claim 1, wherein the melt molding is injection molding or compression molding. 4. The method according to claim 1, wherein the pellets obtained from the resin composition are melt-molded. 5. The method according to claim 1, wherein the heat-meltable resin is a fluorine-containing resin having an MFR value of 0.1 to 100 g / 10 minutes. 6. The fluororesin is a tetrafluoroethylene-perfluoro (alkyl vinyl ether) -based copolymer, a tetrafluoroethylene-ethylene-based copolymer or a tetrafluoroethylene-hexafluoropropylene-based copolymer. 5. The production method according to 5.