JP2018070821A - Method for producing thermoplastic prepreg sheet - Google Patents

Abstract

The present invention provides a thermoplastic prepreg sheet having excellent mechanical strength such as tensile elastic modulus, tensile strength, impact strength, and thermoformability, and a method for producing a laminated thermoplastic prepreg sheet easily and inexpensively. .
A temperature range of an end point and an end point of an endothermic peak obtained from a melting curve of an olefin resin measured by a differential scanning calorimeter by laminating at least one olefin resin sheet and at least one glass cloth. And a method of producing a thermoplastic prepreg sheet, wherein the glass cloth is impregnated with a glass cloth by heating and pressurizing at a pressure of 5 to 100 MPa.
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Description

  The present invention relates to a method for producing a thermoplastic prepreg sheet having excellent mechanical strength such as tensile elastic modulus, tensile strength, impact strength, and thermoformability.

  Conventionally, glass fiber reinforced composite sheets have high mechanical strength such as tensile modulus, tensile strength and impact strength, and are widely used as structural materials for circuit boards, automobiles, ships, railway vehicles, airplanes, containers and sports equipment. Yes.

  Recently, various researches have been conducted on glass fiber reinforced composite sheets using a thermoplastic resin as a matrix, which is easy to heat-press when forming a molded product by molding a glass fiber reinforced composite sheet. As a method for producing a glass fiber reinforced composite sheet, for example, “a method for producing a prepreg containing a thermoplastic resin and a reinforced fiber, wherein the reinforced fiber is 10% or less in the width direction of the basis weight distribution of the reinforced fiber. A temperature at which the zero shear viscosity of the thermoplastic resin becomes 40 to 400 Pa · sec by laminating a thermoplastic resin on the reinforcing fiber and sandwiching the thermoplastic fiber with a pair of supports that run relative to each other. A method for producing a prepreg, which is preheated to a temperature and subsequently subjected to a press with a linear pressure of 20 to 50 kg / cm at a temperature at which the zero shear viscosity of the thermoplastic resin becomes 20 to 400 Pa · sec. ”(For example, see Patent Document 1) Has been proposed.

  However, since the prepreg has roving as the reinforcing fiber, the mechanical strength has directionality and the mechanical strength in the direction parallel to the length direction of the roving is small. There has been proposed a glass fiber reinforced composite sheet using reinforced fiber as a reinforcing fiber. For example, “a prepreg formed by impregnating and solidifying a glass cloth formed by surface treatment with at least a silane coupling agent or an acid-modified polypropylene resin, and the modified polypropylene resin is present in the presence of a radical initiator. Below, a prepreg obtained by reacting a polypropylene resin with an alkylphenol resin ”(for example, see Patent Document 2) has been proposed.

  Since the glass cloth is a reinforced fiber, the prepreg has high mechanical strength and no directionality, and therefore can be suitably used as a glass fiber reinforced composite sheet. However, the polypropylene resin must be reacted with an alkylphenol resin, and the glass cloth must be surface-treated with a silane coupling agent or an acid-modified polypropylene resin. Furthermore, the polypropylene resin-alkylphenol resin reactant is dissolved and supplied onto the glass cloth. It was necessary to press, and it was difficult to manufacture and the manufacturing cost was high.

JP 2014-105310 A Japanese Patent Laying-Open No. 2015-093921

  In view of the above problems, the object of the present invention is to easily and inexpensively produce a thermoplastic prepreg sheet and a laminated thermoplastic prepreg sheet having excellent mechanical strength such as tensile modulus, tensile strength, impact strength, and thermoformability. It is to provide a way to do.

That is, the present invention
[1] Laminated at least one olefin resin sheet and at least one glass cloth, the temperature range of the end point and end point of the endothermic peak determined from the melting curve of the olefin resin measured with a differential scanning calorimeter, And a method for producing a thermoplastic prepreg sheet, wherein the glass cloth is impregnated with a glass cloth by heating and pressurizing at a pressure of 5 to 100 MPa,
[2] The method for producing a thermoplastic prepreg sheet according to the above [1], wherein the glass cloth is composed of glass fiber strands in which 500 to 5000 glass fiber monofilaments having a fiber diameter of 5 to 30 μm are spun.
[3] The method for producing a thermoplastic prepreg sheet according to the above [1] or [2], wherein the glass cloth has a basis weight of 20 to 300 g / m ² .
[4] The thermoplastic prepreg sheet according to the above [1], [2] or [3], wherein the glass cloth is not surface-treated, and
[5] Two or more thermoplastic prepreg sheets according to any one of [1] to [4] above are laminated, and the end point of the endothermic peak determined from the melting curve of the olefin resin measured with a differential scanning calorimeter; The present invention relates to a method for producing a laminated thermoplastic prepreg sheet, characterized by adhering thermoplastic prepreg sheets by heating and pressing at a temperature range of an end point and a pressure of 5 to 100 MPa.

  The structure of the method for producing the thermoplastic prepreg sheet and laminated thermoplastic prepreg sheet of the present invention is as described above. The thermoplastic prepreg having excellent mechanical strength such as tensile elastic modulus, tensile strength, impact strength, and thermoformability, and A laminated thermoplastic prepreg sheet can be produced easily and inexpensively.

  The method for producing a thermoplastic prepreg sheet of the present invention has an endothermic peak obtained by laminating at least one olefin resin sheet and at least one glass cloth and measured by a melting curve of the olefin resin measured with a differential scanning calorimeter. The glass cloth is impregnated with an olefin resin by heating and pressurizing at a temperature range of a starting point and an ending point and a pressure of 5 to 100 MPa.

  As the olefin resin, any olefin resin having film forming ability can be used. For example, high density polyethylene resin, medium density polyethylene resin, low density polyethylene resin, linear low density polyethylene resin, polypropylene resin, polybutene, Polypentene, polyhexene, polyoctene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-pentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene -Vinyl acetate copolymer, ethylene- (meth) acrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-propylene-butene copolymer, etc. are mentioned, and high-density polyethylene resin and polypropylene resin are preferred. used.

  These olefin resins are modified by reacting with an acid-modified olefin resin or alkylphenol resin modified with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid or fumaric acid or its anhydride. It may be an olefin resin. The said olefin resin may be used independently and 2 or more types may be used together.

  When the weight average molecular weight is less than 100,000, the weight average molecular weight of the olefin resin becomes brittle, making it difficult to obtain an olefin resin sheet having sufficient mechanical strength. If it exceeds, the melt viscosity becomes high, the hot melt molding processability decreases, and it becomes difficult to impregnate the glass cloth, so 100,000 to 500,000 is preferable. In the present invention, the weight average molecular weight is a value measured by gel permeation chromatography (GPC).

  The melt mass flow rate (hereinafter referred to as MFR) of the olefin-based resin is preferably 0.1 to 20 g / 10 minutes, more preferably 0.2 to 10 g / 10 minutes, which is excellent in film moldability. Note that MFR is an index representing the melt viscosity of a thermoplastic resin specified in JIS K 7210.

When the density of the olefin-based resin is small, the mechanical strength of the resin sheet is small, and when it is large, the glass cloth is difficult to impregnate and the melt moldability of the obtained resin sheet is lowered, so 0.890 to 0.960 g. / Cm ³ is preferable, and 0.890 to 0.906 g / cm ³ is more preferable.

  The thickness of the olefin-based resin sheet is not particularly limited, but if it is too thick, it is difficult to melt by heating and impregnation into the glass cloth becomes difficult. Conversely, if it is too thin, the amount of resin impregnated into the glass cloth is small. Since it becomes less and it becomes difficult to obtain an olefin resin sheet impregnated with a uniform resin, 0.1 to 15.0 mm is preferable.

  The glass cloth is preferably made of glass fiber strands obtained by spinning glass fiber monofilaments. The glass fiber monofilament is obtained by extruding or drawing molten glass from a nozzle.

  The kind of glass constituting the glass fiber monofilament is not particularly limited. For example, E glass (glass having an alkali content of 2.0% or less), AR glass (alkali resistant glass), C glass (containing acid resistant alkali lime) Glass), D glass (low dielectric constant glass), S glass (high strength, high elastic modulus glass), T glass (high strength, high elastic modulus glass), NE glass (low dielectric constant, low dielectric constant glass), H glass (high dielectric constant glass) and the like.

  If the fiber diameter of the glass fiber monofilament is too thin, it will be difficult to impregnate the olefin resin when it is trended. Conversely, if the fiber diameter is too thick, the bonding area between the glass fiber monofilament and the olefin resin will be reduced, resulting in Since the mechanical strength of the olefin-based resin sheet is lowered, 5 to 30 μm is preferable.

  The glass fiber strand is a glass fiber yarn obtained by spinning the glass fiber monofilament into a yarn shape with a sizing agent. When the number of glass fiber monofilaments to be collected decreases, the glass fiber strands become thin, the number of intersections of the glass fiber strands in the glass cloth increases, and it becomes difficult to impregnate the glass cloth with the olefin resin. Since it becomes difficult for the olefin resin to impregnate into the strand, and as a result, it becomes difficult for the glass cloth to impregnate the olefin resin, it is preferable that 500 to 5,000 are spun.

The glass cloth is a sheet in which the glass fiber strands are woven, and examples of the woven structure include plain weave, twill weave, satin weave, leash weave, and the basis weight is 20 to 300 g / m ^2. preferable. A plurality of glass cloths having a small basis weight may be laminated.

  Since the glass cloth is impregnated with an olefin resin, it is not necessary to surface-treat with a silicon surface treatment agent unlike glass fibers for FRP. It is preferable that the glass cloth is not surface-treated because the olefin resin is easily impregnated.

  In the method for producing a thermoplastic prepreg sheet of the present invention, at least one olefin resin sheet and at least one glass cloth are laminated, and an endothermic peak obtained from a melting curve of the olefin resin measured with a differential scanning calorimeter. The glass cloth is impregnated with an olefin resin by heating and pressurizing at a temperature range of the starting point and ending point of 5 and a pressure of 5 to 100 MPa.

  This temperature is the temperature of the olefin resin, not the temperature of the heating and pressing apparatus. In addition, the end point and end point of the endothermic peak are determined by supplying the olefin resin to a differential scanning calorimeter, heating at a heating rate of 10.0 ° C./mm, holding at 200 ° C. for 3 minutes, and then cooling rate—10. It cools at 0 degreeC / mm and calculates | requires from the melting curve at the time of a 2nd scan. The starting point is the temperature at which the crystal melts and starts to absorb heat as the temperature of the olefin resin rises, and the end point is the temperature at which the melting of the crystal ends.

  At least one olefin-based resin sheet and glass cloth may be laminated, but it is preferable to laminate olefin-based resin sheets on both sides of one or two or more laminated glass cloths. Moreover, you may laminate | stack an olefin resin sheet and a glass cloth alternately so that an outermost layer may become an olefin resin sheet.

  Further, a thick olefin resin sheet may be used as an intermediate layer, and one or two or more olefin resin sheets and glass cloth may be laminated on both sides so that the outermost layer is an olefin resin sheet.

  Next, the temperature range of the end point and end point of the endothermic peak determined from the melting curve of the olefin resin measured with a differential scanning calorimeter for the laminated olefin resin sheet and glass cloth, and at a pressure of 5 to 100 MPa A thermoplastic prepreg sheet is obtained by impregnating glass cloth with an olefin resin by heating and pressurization.

  In the present invention, since the glass cloth is impregnated with the olefin resin sheet that is not completely melted, it becomes difficult to impregnate the glass cloth with the olefin resin sheet when the heating temperature is low and the pressure is low. Further, when the heating temperature is increased, the fluidity of the olefin resin is improved and the glass cloth is easily impregnated. However, when the heating temperature is excessively high, the fluidity of the olefin resin is excessively improved and the pressure is increased. Since it becomes difficult to obtain a thermoplastic prepreg sheet having a uniform thickness, it is limited to the above temperature range and pressure range. The heating and pressing time may be appropriately determined depending on the number of olefin resin sheets and glass cloth to be pressed, the heating temperature and the pressing pressure, but is generally 1 to 10 minutes.

  As the heating and pressing method, any conventionally known heating and pressing method may be employed, and examples thereof include a hot press molding method, a heating roll molding method, and an endless belt heating and pressing method.

  The production method of the laminated thermoplastic prepreg sheet of the present invention is obtained by laminating two or more thermoplastic prepreg sheets produced by the production method described in any one of [1] to [4] above, and measuring with a differential scanning calorimeter. The thermoplastic prepreg sheets are bonded to each other by heating and pressurizing at a temperature range of the end point and end point of the endothermic peak determined from the melting curve of the olefin resin and a pressure of 5 to 100 MPa.

  Two or more thermoplastic prepreg sheets produced by the method for producing a thermoplastic prepreg sheet according to any one of [1] to [4] above are laminated, and the thermoplastic prepreg sheets are bonded to each other, thereby increasing the thickness. A laminated thermoplastic prepreg sheet is obtained.

  Further, a low melting point resin sheet such as a linear low density polyethylene resin or an ethylene-vinyl acetate copolymer may be interposed between two or more thermoplastic prepreg sheets.

  The thermoplastic prepreg sheet and the laminated thermoplastic prepreg sheet obtained by the method for producing the thermoplastic prepreg sheet of the present invention and the method for producing the laminated thermoplastic prepreg sheet are formed by impregnating the glass cloth with an olefin resin. Excellent mechanical strength such as elastic modulus, tensile strength and impact strength. In addition, since the olefin resin is thermoplastic, the thermoplastic prepreg sheet and the laminated thermoplastic prepreg sheet can be heat-molded not only by press molding but also by vacuum molding, pressure molding, etc., and can form various deformed shapes. It is possible.

  A copper-clad board can be obtained by laminating and pressing a copper plate on at least one surface of the thermoplastic prepreg sheet or the laminated thermoplastic prepreg sheet, and a printed circuit board by forming a circuit pattern of a predetermined shape on the copper plate. Can be obtained.

  The copper-clad substrate is, for example, a copper plate laminated on at least one surface of a thermoplastic prepreg sheet or a laminated thermoplastic prepreg sheet, and an endothermic peak starting point obtained from a melting curve of an olefin resin measured with a differential scanning calorimeter, It is manufactured by bonding the thermoplastic prepreg sheet or the laminated thermoplastic prepreg sheet and the copper plate by heating and pressing at a temperature range of the end point and a pressure of 5 to 100 MPa for about 1 to 10 minutes.

  Next, examples of the present invention will be described, but the present invention is not limited to the examples.

Example 1
A glass fiber strand in which 2000 glass fiber monofilaments having a fiber diameter of 17 μm are spun is plain-woven, and a polypropylene resin sheet (thickness: 0.15 mm) is formed on both surfaces of a glass cloth (weight per unit area: 200 g / m ² ) that is not surface-treated. Weight average molecular weight (Mw) 330,000, MFR 0.90 g / 10 min, density 0.900 g / cm ³ , melting point 165 ° C.) are laminated, supplied to a press machine, press-molded at 170 ° C. and 10 MPa for 1 minute, A polypropylene prepreg sheet having a thickness of 0.38 mm was obtained. The polypropylene resin was uniformly impregnated into the glass cloth.

  After cutting the polypropylene resin sheet and supplying it to a differential scanning calorimeter (Shimadzu Corporation, Shimadzu High Sensitivity Thermal Analyzer 600 Series), heating at a heating rate of 10.0 ° C./mm and holding at 200 ° C. for 3 minutes The sample was cooled at a cooling rate of 10.0 ° C./mm, and the melting curve at the second scan was measured. The end point of the endothermic peak was 129 ° C. and the end point was 173 ° C.

(Example 2)
Glass fiber strands obtained by spinning 2000 glass fiber monofilaments having a fiber diameter of 17 μm were plain woven, and were subjected to corona treatment having a thickness of 0.20 mm on both surfaces of a glass cloth (weight per unit area: 220 g / m ² ) that was not surface-treated. A polypropylene resin sheet (weight average molecular weight (Mw) 330,000, MFR 0.90 g / 10 min, density 0.900 g / cm ³ , melting point 165 ° C.) is laminated, supplied to a press machine, and pressed at 170 ° C. and 10 MPa for 1 minute. Molding was performed to obtain a polypropylene prepreg sheet having a thickness of 0.48 mm. The polypropylene resin was uniformly impregnated into the glass cloth.

  The polypropylene resin sheet was cut and the melting curve was measured in the same manner as in Example 1. The endothermic peak derived from the main raw material polypropylene resin and the endothermic peak derived from the linear low-density polyethylene resin considered as an additive were found. Observed, the start and end points were 110 ° C. and 176 ° C. and 90 ° C. and 115 ° C., respectively.

(Example 3)
The polypropylene prepreg sheets obtained in Example 1 and Example 2 were laminated, supplied to a press, and press molded at 173 ° C. and 20 MPa for 30 seconds to obtain a laminated thermoplastic prepreg sheet having a thickness of 0.88 mm. .

(Comparative Example 1)
A glass fiber strand in which 2000 glass fiber monofilaments having a fiber diameter of 17 μm are spun is plain-woven, and a polypropylene resin sheet (thickness: 0.15 mm) is formed on both surfaces of a glass cloth (weight per unit area: 200 g / m ² ) that is not surface-treated. Weight average molecular weight (Mw) 330,000, MFR 0.90 g / 10 min, density 0.900 g / cm ³ , melting point 165 ° C.), supplied to a press machine, press-molded at 110 ° C. and 10 MPa for 1 minute, A polypropylene prepreg sheet having a thickness of 0.40 mm was molded, but the polypropylene resin did not melt and an impregnated glass sheet could not be obtained. When press molding was performed at 180 ° C. and 10 MPa for 1 minute, the polypropylene resin flowed and impregnated, but the glass cloth fibers flowed together with the polypropylene resin, and a good sheet could not be obtained.

  The tensile strength and tensile elastic modulus of the thermoplastic prepreg sheets and laminated thermoplastic prepreg sheets obtained in Examples 1 to 3 were measured according to JIS K 7113. The results are shown in Table 1.

For reference, the tensile strength and tensile elasticity of a polypropylene resin sheet having a thickness of 0.40 mm (weight average molecular weight (Mw) 330,000, MFR 0.90 g / 10 min, density 0.900 g / cm ³ , melting point 165 ° C.) The rate was measured according to JIS K 7113, and the results are shown in Table 1. When the melting curve was measured in the same manner as in Example 1, the end point of the endothermic peak of this polypropylene resin sheet was 129 ° C, the end point was 173 ° C, and the content of the linear low-density polyethylene resin was small. The endothermic peak derived from the linear low density polyethylene resin was not clearly observed.

  The thermoplastic prepreg sheet and laminated thermoplastic prepreg sheet of the present invention can be suitably used as a structural material, an insulating material for a storage battery, and a circuit board.

Claims (5)

  At least one olefin resin sheet and at least one glass cloth are laminated, and the temperature range of the end point and end point of the endothermic peak determined from the melting curve of the olefin resin measured with a differential scanning calorimeter, and 5 A method for producing a thermoplastic prepreg sheet, comprising heating and pressurizing at a pressure of -100 MPa and impregnating a glass cloth with an olefin resin.   2. The method for producing a thermoplastic prepreg sheet according to claim 1, wherein the glass cloth comprises glass fiber strands obtained by spinning 500 to 5000 glass fiber monofilaments having a fiber diameter of 5 to 30 [mu] m. Glass cloth, according to claim 1 or 2 thermoplastic prepreg sheet manufacturing method as set forth, wherein the basis weight is 20 to 300 g / m ^2.   4. The method for producing a thermoplastic prepreg sheet according to claim 1, wherein the glass cloth is not subjected to surface treatment.   The temperature range of the end point and the end point of the endothermic peak obtained from the melting curve of the olefin-based resin measured by a differential scanning calorimeter by laminating two or more thermoplastic prepreg sheets according to any one of claims 1 to 4. And a method of producing a laminated thermoplastic prepreg sheet, comprising heating and pressurizing at a pressure of 5 to 100 MPa, heating and pressurizing at a pressure of 10 to 100 MPa, and bonding the thermoplastic prepreg sheets together.