JPH0639895A - Reinforced sheet of polyethyene naphthalate - Google Patents

Abstract

PURPOSE:To provide a fiber-reinforced polyethylene naphthalate resin sheet with excellent dimensional stability, heat resistance, surface smoothness and mechanical strength and little anisotropy on mechanical characteristics. CONSTITUTION:A reinforced sheet obtd. by extrusion molding of a compsn. wherein 5-50 pts.wt. inorg. compd. with a mean particle diameter of at most 100mum and 2-50 pts.wt. fibrous reinforcing material are incorporated in 100 pts.wt. polyethylene naphthalate resin. When heat-treatment is performed pref. at 160 deg.C or higher after extrusion molding, the mechanical properties and thermal properties are furthermore improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforced sheet obtained by extrusion molding a specific composition containing a polyethylene naphthalate resin as a main component. More specifically, it relates to a composite sheet using a polyethylene naphthalate resin as a matrix resin, which is excellent in dimensional stability, heat resistance, surface smoothness, mechanical strength, and has a small anisotropy in mechanical properties such as bending strength. It can be used for a wide range of applications such as electrical insulation boards, mechanical parts, and structural materials.

[0002]

2. Description of the Related Art Polyethylene naphthalate resin belongs to polyester resins and has a glass transition temperature of 40 ° C. or more higher than that of polyethylene terephthalate resin, which is a typical resin. 155 ° C (JIS C400)
According to 3 [kind of insulation of electric equipment], it is called F type) and has heat resistance much higher than 120 ° C. (class E type) of polyethylene terephthalate resin. Further, it has excellent chemical resistance, hydrolysis resistance, gas barrier property, and dimensional stability, and is attracting attention as an engineering plastic stick. That is, it has attracted attention as a resin having higher performance than polyethylene terephthalate resin, and has been developed as a film, a resin composition and the like for electrical insulation, magnetic recording and the like. Usually, polyethylene naphthalate resin is
In order to improve mechanical properties, it is reinforced with a fibrous reinforcing material such as glass fiber, and when extruded into a sheet, the polyethylene naphthalate resin molecules and the fibrous reinforcing material are oriented, and the extrusion direction ( There are problems that the mechanical properties in the width direction (TD direction) are significantly inferior to those in the MD direction) and that the sheet has a large surface roughness due to the influence of the fibrous reinforcing material.

[0003]

DISCLOSURE OF THE INVENTION The present invention uses a resin composition in which a polyethylene naphthalate resin is used as a matrix resin and is mixed with a fiber reinforcement and the like, and is excellent in mechanical strength and in the MD and TD directions. The object is to obtain an extruded sheet with a small difference in mechanical properties and an excellent surface smoothness, and to obtain a relatively inexpensive reinforced sheet with excellent heat resistance and dimensional stability using this extruded sheet. To do.

[0004]

Means for Solving the Problems The present invention is to solve the above problems, and the gist thereof is an inorganic compound ((A) having an average particle size of 100 μm or less with respect to 100 parts by weight of a polyethylene naphthalate resin. 5 to 50 parts by weight and fibrous reinforcing material (B) 2 to
It is a reinforced sheet obtained by extruding a composition containing 50 parts by weight. In this case, it is more preferable that the reinforced sheet has a higher degree of crystallinity by heat treatment after extrusion molding. Hereinafter, the present invention will be described in detail.

The polyethylene naphthalate resin in the present invention may be a polymer composed of only ethylene-2,6 naphthalate constitutional units (polyethylene-2,6 naphthalate), but contains ethylene-2,6 naphthalate constitutional units as a main component. A polymer containing a small amount of a structural unit selected from an ethylene-2,7-naphthalate structural unit, an ethylene-1,5-naphthalate structural unit, and an ethylene-1,4-naphthalate structural unit may be used. The polyethylene naphthalate resin in the present invention is prepared to have a concentration of 0.5 g / dl using an equal weight mixed solvent of phenol / tetrachloroethane, and has an intrinsic viscosity of 0 measured at 20 ° C. using an Ubbelohde viscometer. It is preferable to use one having a value of 0.50 or more, preferably 0.60 or more. By using one having an intrinsic viscosity of 0.5 or more, excellent mechanical properties can be obtained, and a uniform sheet can be easily obtained by extrusion molding. The reinforced sheet of the present invention is obtained by extrusion-molding a composition obtained by blending such a polyethylene naphthalate resin with a specific amount of the fine particulate inorganic compound (A) and the fibrous reinforcing material (B).

Specific examples of the finely divided inorganic compound (A) that can be used in the present invention include silica, calcium carbonate, synthetic silicic acid or silicate, zinc oxide, halosite clay, kaolin, basic magnesium carbonate, Examples thereof include talc, mica, quartz powder, wollastonite, dolomite powder, titanium oxide, barium sulfate, calcium sulfate, and alumina, but mica, talc and wollastonite are particularly preferable. The inorganic compound needs to have an average particle size of 100 μm or less, preferably 80 μm or less. If it is larger than 100 μ, the effect of relaxing the anisotropy of the reinforcing sheet and improving the surface smoothness is poor.

Specific examples of the fibrous reinforcing material (B) that can be used in the present invention include glass fiber, carbon fiber, aromatic polyamide fiber, silicon carbide fiber, potassium titanate fiber, and the like. Is preferably used. The length and thickness of the fibrous reinforcing material are not particularly limited, but if the length is too short, the effect as a reinforcing material is poor, and if it is too long, it is difficult to uniformly disperse the fibrous reinforcing material. 1 to 10 mm is used. When glass fiber is used as the fibrous reinforcing material, it is preferable to use one having a fiber length of 0.1 to 7 mm, particularly 0.3 to 5 mm. The fibrous reinforcing material is optionally treated with various surface treating agents for the purpose of enhancing the interfacial adhesion with the polyethylene naphthalate resin and enhancing the reinforcing effect. For example, in the case of glass fiber, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyl Those treated with a silane coupling agent such as triethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane or a chromium coupling agent such as methacrylate chromic chloride are used.

When the reinforcing sheet of the present invention is used for an electric insulating board, it is desirable to use an electrically insulating material as the finely divided inorganic compound (A) and the fibrous reinforcing material (B). A conductive material may be used together as long as the amount is small.

The amount of the finely divided inorganic compound (A) is 5 to 50 with respect to 100 parts by weight of the polyethylene naphthalate resin.
Parts by weight, preferably 5 to 40 parts by weight. If the amount of the finely divided inorganic compound is less than 5 parts by weight, the effect of relaxing the anisotropy of the reinforcing sheet and improving the surface smoothness is insufficient, and if it exceeds 50 parts by weight, Mechanical properties are significantly reduced. Fibrous reinforcement (B)
The same amount of polyethylene naphthalate resin 100
2 to 50 parts by weight, preferably 10 to 4 parts by weight
It is necessary to set the range to 0 parts by weight. If the amount of the fibrous reinforcing material is less than 2 parts by weight, the effect as the reinforcing material is insufficient, and if it exceeds 50 parts by weight, the surface smoothness of the reinforcing sheet is significantly deteriorated. It is desirable that the total amount of the finely divided inorganic compound and the fibrous reinforcing material be 65 parts by weight or less. If the total blending amount exceeds 65 parts by weight, strand breaks will frequently occur during the production of the compound (pellet), and the operability of the compound production will decrease, which is not preferable.

In addition to the finely divided inorganic compound (A) and the fibrous reinforcing material (B), if necessary, a heat stabilizer, an antioxidant, a light stabilizer, a lubricant, a pigment, a flame retardant, a plasticizer, You may mix | blend additives, such as an impact resistance agent.

Reinforcement sheet of the present invention (before heat treatment)
Is flexible and can be used for deep drawing or the like by thermoforming treatment, but it is more suitable as an industrial reinforcing sheet by heat treatment to increase the crystallinity.

When the reinforced sheet of the present invention is used as an industrial reinforced sheet, it is necessary to heat-treat (for example, heat-roll) to increase the crystallinity. In this case, the crystallinity is 10% or more. Is desirable. Industrial reinforced sheets are required to have excellent mechanical strength, heat resistance, chemical resistance, etc., as well as dimensional stability and warpage resistance, but reinforced sheets before heat treatment do not have sufficient dimensional stability. Is hard to say. Dimensional stability is improved by further heat-treating a reinforced sheet in which a mechanical strength is increased by mixing a polyethylene naphthalate resin, which has excellent heat resistance and chemical resistance, with a reinforcing material, and further heat-treating it. At the same time, the mechanical properties and thermal properties are further improved, and it becomes suitable as an industrial reinforcing sheet. As a heat treatment method after such extrusion molding, it is preferable to press and heat with a press. The pressing pressure at that time is 10 kg / sheet pressure.
cm ² or more, pressing temperature is 130 ° C as sheet temperature
The above is preferable, and 160 ° C. or more is particularly preferable.

[0013]

【Example】

(Examples 1 to 3) 100 parts by weight of polyethylene 2,6 naphthalate having an intrinsic viscosity of 0.90 was mixed with the glass fibers and mica shown in Table 1 at a ratio shown in Table 1, and a twin-screw extruder (Toshiba Machinery) was used. Discharge rate 200k by TEM70)
Melt kneading was performed at a temperature of 300 ° C. for g / hour to prepare pellets. After vacuum-drying this at 170 ° C. for 6 hours, it is 1 mm at a temperature of 280 ° C. by an extrusion sheet molding machine using a T die.
When formed into a pressure sheet, a sheet having a smooth surface and good appearance as shown in Table 2 could be obtained. Further, when the bending strength was measured, the physical property value with low anisotropy was shown.

(Comparative Examples 1 to 5) 100 parts by weight of polyethylene 2,6 naphthalate used in Examples 1 to 3 was mixed with glass fibers or mica at a ratio shown in Table 1 to prepare Examples 1 to 3. Pellets were prepared in the same manner as above, and a sheet was obtained by using the pellets with an extrusion sheet forming apparatus. Table-3
Comparative Example 1 containing 60 parts by weight of glass fiber as shown in FIG.
Then, the sheet surface was in a rough state. Further, in Comparative Example 2 in which 30 parts by weight of mica (particle size 40 μm) was added without compounding glass fiber, it was found that the bending strength was low and there was a practical problem. Even in Comparative Example 3 in which 60 parts by weight of mica was added, the bending strength was low and it was found that there was a problem in practical use. The surface of the sheet was also in a slightly rough state. In Comparative Example 4 in which 30 parts by weight of glass fiber alone was blended without blending mica, strong anisotropy appeared. Moreover, as in Comparative Example 5, when mica having a particle size of 120 μ was used, the bending strength in the TD direction was significantly reduced.

(Examples 4 to 6) The sheets obtained in Example 2 were subjected to a 20-stage multi-stage press forming machine at the temperatures shown in Table-4,
After pressing at a pressing surface pressure of 50 kg / cm ² for 1 hour, the press was cooled with a water cooling method while maintaining the pressure, and the temperature was lowered to room temperature. Then, the pressure was released and the product was taken out. The crystallinity, flexural strength, flexural modulus, deformation rate, and heat shrinkage rate of the obtained reinforcing sheet were measured, and the results are shown in Table 4, showing good physical properties.

(Comparative Examples 7-11, Reference Example) Comparative Examples 1-5
The sheet obtained in 1 above was treated at a temperature of 17 in the same manner as in Examples 4 to 6.
It was press molded at 0 ° C. Also, the sheet of Example 2 is 120
Press molding was performed at a temperature of ° C in the same manner as in Examples 4 to 6 (Reference Example). The physical properties of the obtained reinforcing sheet are shown in Tables 5 and 6.

The methods of measuring physical properties and the like and the methods of evaluation are as follows. [Bending strength] According to ASTM D790. [Flexural Modulus] Based on ASTM D790. [Crystallinity] It was measured by the infrared total reflection absorption spectrum method. According to [HDT] ASTM D648, a 1/8 inch thick test piece was used and the load was measured at 18.6 Kg / cm ² . [Heat Shrinkage] A sheet with a thickness of 1 mm is heated to 200 ° C in a hot air oven.
After being heat-treated for 1 hour at room temperature, it was allowed to cool to room temperature and calculated from the thermal shrinkage of dimensions.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

[0021]

[Table 4]

[0022]

[Table 5]

[0023]

[Table 6]

[0024]

As described in detail above, the reinforcing sheet obtained from the polyethylene naphthalate resin composition containing the fine particulate inorganic compound and the fibrous reinforcing material of the present invention has the mechanical properties of polyethylene naphthalate resin. In addition to being utilized, the difference in mechanical properties in the MD and TD directions is small, and the surface smoothness is excellent. Also,
By heat-treating this reinforcing sheet, a reinforcing sheet having further excellent performance can be obtained at a relatively low cost.

[Procedure amendment]

[Submission date] October 1, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art Polyethylene naphthalate resin belongs to polyester resins and has a glass transition temperature of 40 ° C. or more higher than that of polyethylene terephthalate resin, which is a typical resin. 155 ° C (JIS C400)
According to 3 [kind of insulation of electric equipment], it is called F type) and has heat resistance much higher than 120 ° C. (class E type) of polyethylene terephthalate resin. Further, it has excellent chemical resistance, hydrolysis resistance, gas barrier property, and dimensional stability, and is attracting attention as an engineering plastic. That is, it has attracted attention as a resin having higher performance than polyethylene terephthalate resin, and has been developed as a film, a resin composition and the like for electrical insulation, magnetic recording and the like. Usually, polyethylene naphthalate resin is used by being reinforced with a fibrous reinforcing material such as glass fiber in order to improve mechanical properties, but when extruded into a sheet, polyethylene naphthalate resin molecule and fibrous reinforcing material are used. The material is oriented, and the width direction (T
There is a problem that the mechanical properties in the D direction) are remarkably inferior, and the sheet has a large surface roughness due to the influence of the fibrous reinforcing material.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

The amount of the finely divided inorganic compound (A) is 5 to 50 with respect to 100 parts by weight of the polyethylene naphthalate resin.
Parts by weight, preferably 5 to 40 parts by weight. If the amount of the finely divided inorganic compound is less than 5 parts by weight, the effect of relaxing the anisotropy of the reinforcing sheet and improving the surface smoothness is insufficient, and if it exceeds 50 parts by weight, Mechanical properties are significantly reduced. Fibrous reinforcement (B)
The same amount of polyethylene naphthalate resin 100
2 to 50 parts by weight, preferably 10 to 4 parts by weight
It is necessary to set the range to 0 parts by weight. If the amount of the fibrous reinforcing material is less than 2 parts by weight, the effect as the reinforcing material is insufficient, and if it exceeds 50 parts by weight, the surface smoothness of the reinforcing sheet is significantly deteriorated. It is desirable that the total amount of the finely divided inorganic compound and the fibrous reinforcing material be 65 parts by weight or less. If the total blending amount exceeds 65 parts by weight, strand breaks will frequently occur during the production of compounds (pellets), and the operability of compound production will decrease, which is not preferable.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location C08K 7/02 KKF 7242-4J C08L 67/02 KJQ 8933-4J // B29K 67:00 105: 06 (72) Inventor Mikio Kusunou, Uji City, Uji City, Kyoto Prefecture 3 31 Uji-Hijiri, Unitika Co., Ltd. Uji Plastic Factory in the factory

Claims (2)

[Claims] 1. 100 parts by weight of a polyethylene naphthalate resin, 5 to 50 parts by weight of an inorganic compound (A) having an average particle diameter of 100 μm or less, and 2 to 5 of a fibrous reinforcing material (B).
A reinforced sheet obtained by extrusion molding a composition containing 0 part by weight. 2. The reinforced sheet according to claim 1, which is obtained by heat treatment at a temperature of 160 ° C. or higher after extrusion molding.