JP2016216661A - Manufacturing method of composite sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a composite sheet to which a xylylene-based polyamide resin impregnates easily.SOLUTION: The manufacturing method of a composite sheet includes impregnating a polyamide resin containing a constitutional unit derived from diamine and a constitutional unit derived from dicarboxylic acid, where 50 mol% or more of the constitutional unit derived from diamine is derived from xylylenediamine, and having moisture content measured by Karl Fischers' method of 1 wt.% or more into a reinforced fiber sheet.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a composite sheet in which a reinforcing fiber is impregnated with a polyamide resin.

Conventionally, composite sheets obtained by impregnating reinforcing fibers with polyamide resin have been widely studied. In particular, a polyamide resin containing a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 50 mol% or more of the structural unit derived from diamine is derived from xylylenediamine (hereinafter sometimes referred to as “xylylene-based polyamide resin”). A composite sheet impregnated with reinforced fibers is attracting attention because it is light and exhibits high mechanical strength.
For example, Patent Document 1 describes a composite material obtained by impregnating a predetermined xylylene-based polyamide resin into a fiber material.

International Publication WO2012 / 140785 Pamphlet

Here, as a result of investigation by the present inventors, when a composite sheet is produced by impregnating a reinforcing fiber with a xylylene-based polyamide resin, if the target composite sheet is thick, the xylylene-based polyamide resin becomes a reinforcing fiber. It turned out that it became difficult to impregnate a center part.
The present invention aims to solve such problems, and is a method for producing a composite sheet in which a reinforcing fiber is impregnated with a xylylene-based polyamide resin, and the xylylene-based polyamide resin is easily impregnated into the composite fiber. It aims at providing the manufacturing method of a composite sheet.

As a result of studies by the present inventors under such problems, it has been found that the above problems can be solved by including a predetermined amount of moisture in the xylylene-based polyamide resin impregnated in the reinforcing fibers. Specifically, the above problem has been solved by the following means <1>, preferably by <2> to <14>.
<1> A polyamide resin containing a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, wherein 50 mol% or more of the structural unit derived from the diamine is derived from xylylenediamine, and the moisture content measured by the Karl Fischer method A method for producing a composite sheet, comprising impregnating a reinforcing fiber sheet with a polyamide resin having a water content of 1% by weight or more and a saturated water content or less.
<2> The method for producing a composite sheet according to <1>, wherein the polyamide resin is a polyamide resin film.
<3> The method for producing a composite sheet according to <2>, wherein three or more polyamide resin films and two or more reinforcing fiber sheets are alternately laminated and impregnated.
<4> The method for producing a composite sheet according to any one of <1> to <3>, wherein the total basis weight of the reinforcing fiber sheet is 10 to 10,000 g / m ² .
<5> The method for producing a composite sheet according to any one of <1> to <4>, wherein the total thickness of the reinforcing fiber sheet is 0.05 to 10 mm.
<6> The polyamide resin has a melt viscosity of 500 Pa · s or less under the conditions of a melting point of + 35 ° C., a holding time of 6 minutes, and an apparent shear rate of 36.5 s ⁻¹ , <1> to <5> The manufacturing method of the composite sheet in any one of.
<7> The method for producing a composite sheet according to any one of <1> to <6>, wherein an impregnation ratio of the polyamide resin into the reinforcing fiber in the composite sheet is 90% or more.
<8> The method for producing a composite sheet according to any one of <1> to <7>, wherein a ratio of reinforcing fibers in the composite sheet is 10 to 65% by weight.
<9> The composite sheet according to any one of <1> to <8>, wherein the xylylenediamine is metaxylylenediamine, paraxylylenediamine, or a mixture of metaxylylenediamine and paraxylylenediamine. Manufacturing method.
Any one of <1> to <9>, wherein 50 mol% or more of the structural unit derived from <10> dicarboxylic acid is a structural unit derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. A method for producing the composite sheet according to 1.
The manufacturing method of the composite sheet in any one of <1>-<9> whose 50 mol% or more of the structural unit derived from <11> dicarboxylic acid is a structural unit derived from sebacic acid.
<12> The impregnation step includes pressurization at 1 to 6 MPa for 10 to 1000 seconds at a temperature of the melting point of the polyamide resin + 10 ° C. to the melting point + 100 ° C., according to any one of <1> to <11>. A method for producing a composite sheet.
<13> The method for producing a composite sheet according to any one of <1> to <12>, wherein the composite sheet has a thickness of 200 μm to 20 mm.
<14> The method for producing a composite sheet according to any one of <1> to <13>, wherein the reinforcing fiber is at least one of carbon fiber and glass fiber.

  According to the present invention, it is possible to provide a method for producing a composite sheet in which a xylylene polyamide resin is easily impregnated into a reinforcing fiber.

It is the schematic which shows the process of impregnating a reinforcement fiber with a xylylene-type polyamide resin. It is the schematic which shows the process of alternately laminating | stacking a some xylylene-type polyamide resin film and a some reinforcement fiber sheet, and making a reinforcement fiber impregnate a xylylene-type polyamide resin. It is the schematic which shows the process of heat-pressing what laminated | stacked the polyamide resin film and the reinforced fiber sheet alternately between a pair of rolls.

Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
In addition, the code | symbol in drawing is common in FIGS. 1-3.

The method for producing a composite sheet of the present invention comprises a polyamide resin comprising a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, wherein 50 mol% or more of the structural unit derived from the diamine is derived from xylylenediamine, The reinforcing fiber sheet is impregnated with a polyamide resin having a moisture content measured by the Fischer method of 1% by weight or more and a saturated moisture content or less. In the present invention, the reinforcing fiber can be appropriately impregnated with the xylylene-based polyamide resin by adopting such a configuration.
As an example of the form in which the reinforcing fiber sheet is impregnated with the xylylene-based polyamide resin, as shown in FIG. 1, the xylylene-based polyamide resin film 2 is stacked on both sides of the reinforcing fiber sheet 1, and the xylylene-based polyamide resin film 2 is heated (melted). And pressurizing and impregnating the reinforcing fiber sheet 1 to obtain the composite sheet 3. Here, if the basis weight of the reinforcing fiber sheet is small, the impregnation proceeds relatively smoothly. However, when the basis weight of the reinforcing fiber sheet is increased, the resin is less likely to be impregnated and may not be sufficiently impregnated to the center. In this regard, if the heating temperature and the pressure to be applied at the time of impregnation are increased or the heating / pressurizing time is lengthened, the impregnation can be performed up to the central portion. However, it is not desirable from the viewpoint of productivity. On the other hand, in the present invention, the impregnation property is enhanced by adding moisture to the xylylene-based polyamide resin.
In FIG. 1, two xylylene-based polyamide resin films may be stacked on both sides of the reinforcing fiber sheet 1, or one xylylene-based polyamide resin film may be stacked on both sides of the two reinforcing fiber sheets. It may be in the form of overlapping one by one. However, it is preferable to alternately laminate the xylylene-based polyamide resin film and the reinforcing fiber sheet. The xylylene-based polyamide resin film preferably has uneven texture on the surface. By adopting such a configuration, there is an advantage that the unwinding property from the resin film roll and the stacking property with the reinforcing fiber are improved and the operation becomes easy.
FIG. 2 is another example of a form in which a reinforcing fiber sheet is impregnated with a xylylene-based polyamide resin. Three or more polyamide resin films 2 and two or more reinforcing fiber sheets 1 are alternately laminated and impregnated. An embodiment is shown. Thus, when the number of reinforcing fiber sheets increases, the total basis weight of the reinforcing fiber sheets tends to be relatively large. In this state, when pressure is applied from the upper surface and the lower surface of the film (in the direction of the arrow in FIG. 2), the reinforcing fiber sheet in the central portion tends to be less likely to be impregnated with the polyamide resin. However, in the present invention, the xylylene-based polyamide resin has been successfully impregnated by impregnating it up to the center by impregnating it with moisture.
The reason why the xylylene-based polyamide resin is easily impregnated when the water content is increased is presumed that when the xylylene-based polyamide resin contains water, the melt viscosity of the xylylene-based polyamide resin is lowered and the impregnation is facilitated.
In addition, in FIG. 2, when using a fiber reinforced sheet in which reinforcing fibers are arranged in one direction as the reinforcing fiber sheet, the fiber directions of the reinforcing fibers of the first layer reinforcing fiber sheet and the second layer reinforcing fiber sheet are: It is preferable to laminate so as to intersect with each other, and the third and subsequent layers are also preferably laminated so as to intersect similarly.

<Impregnation process>
In the present invention, as described above, the reinforcing fiber sheet is impregnated with the xylylene-based polyamide resin. The method for impregnation is not particularly defined, but the xylylene-based polyamide resin is heated and melted to impregnate the reinforcing fiber sheet. At this time, usually, pressure is applied.
The heating temperature of the xylylene-based polyamide resin is preferably the melting point of the xylylene-based polyamide resin + 10 ° C. to the melting point + 100 ° C., more preferably the melting point of the xylylene-based polyamide resin + 20 ° C. to the melting point + 90 ° C., more preferably 25-50 ° C. When the xylylene polyamide resin has two or more melting points, the melting point is set to the higher melting point. Moreover, when using together 2 or more types of xylylene-type polyamide resins, let the highest melting | fusing point be the said melting | fusing point among 2 or more types of xylylene-type polyamide resins.
In the present invention, since the moisture content of the xylylene-based polyamide resin is 1% by weight or more, even if the total weight of the reinforcing fiber sheet is large, it is appropriately impregnated even if the temperature is not higher than the conventional one. Is possible.
In the impregnation, when pressure is applied, the pressure is preferably 1 to 6 MPa, more preferably 2 to 5 MPa. In the present invention, since the moisture content of the xylylene-based polyamide resin is 1% by weight or more, even if the total basis weight of the reinforcing fiber sheet is large, it can be appropriately impregnated even if the pressure is not higher than the conventional one. Is possible.
In the impregnation, the heating and / or pressurizing time is preferably 10 to 1000 seconds, and more preferably 10 to 800 seconds. In the present invention, since the water content of the xylylene-based polyamide resin is 1% by weight or more, it can be appropriately impregnated with a shorter heating time and pressurization time than the total weight of the reinforcing fiber sheet.
Heating and pressurization may be performed simultaneously or separately. As an example of performing heating and pressurization simultaneously, a heat press is exemplified.
Moreover, as shown in FIG. 3, you may heat and pressurize what laminated | stacked the polyamide resin film 2 and the reinforced fiber sheet 1 by hot-pressing between a pair of rolls. That is, it is preferable to heat by using a roll in a state in which the reinforcing fiber sheets are sandwiched (alternately laminated) with a polyamide resin film. Either the upper roll 4 or the lower roll 5 in FIG. 3 may be a heated roll, or only the upper roll is a heated roll and the lower roll is an unheated roll (for example, the melting point of the xylylene-based polyamide resin). A roll having a temperature lower than that). Moreover, when a heating roll adheres to a xylylene-type polyamide resin film, you may arrange | position a release sheet etc. between a heating roll and a xylylene-type polyamide resin film.

In the present invention, the xylylene-based polyamide resin is usually melted and impregnated into the reinforcing fiber sheet. However, the form of the xylylene-based polyamide resin before melting is not particularly defined, and in addition to the above-mentioned film shape, The thing of the form of is also employable. In the present invention, a film-like xylylene-based polyamide resin (xylylene-based polyamide resin film) is preferable from the viewpoint of productivity.
The thickness of the xylylene-based polyamide resin film can be appropriately determined according to the thickness of the composite sheet and the content of reinforcing fibers in the composite sheet. For the thickness of the polyamide resin film, for example, the upper limit value can be less than 250 μm, preferably 200 μm or less, the lower limit value can be 30 μm or more, and preferably 50 μm or more.

<Winding process>
The composite film in which the reinforcing fiber sheet is impregnated with the xylylene-based polyamide resin can then be wound up by a winding roll. That is, the composite sheet obtained by the production method of the present invention may be a wound body.
Of course, it is needless to say that an aspect of cutting into a desired size after impregnation is also included in the scope of the present invention.

<Properties of composite sheet>
The thickness of the composite sheet in the present invention is not particularly defined, but the lower limit is preferably 200 μm or more, more preferably 250 μm or more, further preferably 500 μm or more, more preferably 800 μm or more, and more preferably 1 mm or more. Is even more preferable. The upper limit is preferably 20 mm or less, more preferably 10 mm or less, still more preferably 5 mm or less, still more preferably 4 mm or less, and even more preferably 3 mm or less. Here, the thickness of the composite sheet refers to the thickness measured according to JIS-K 7130-1999.
Although the width | variety of the composite sheet in this invention is not specifically defined, For example, it can be set as 5 mm-2000 mm, and 120 mm-2000 mm are preferable. The length of the composite sheet of the present invention is not particularly defined, but may be a continuous composite sheet or a composite sheet cut into a desired shape. The length of the continuous composite sheet is preferably in the range of 1 to 10,000 m. The length of the composite sheet cut into a desired shape is preferably in the range of 3 cm to 2 m.
The composite sheet of the present invention preferably has a weight per m ^{2 of} 50 to 3000 g, more preferably 100 to 2000 g.

<< impregnation rate >>
The impregnation ratio of the xylylene-based polyamide resin into the reinforcing fiber in the composite sheet of the present invention is preferably 90% or more, more preferably 95% or more, and further preferably 99% or more. On the other hand, the upper limit of the impregnation rate is not particularly defined and may be 100%. By increasing the impregnation rate in this way, a composite sheet stronger against vibration can be obtained.
The impregnation rate in the present invention refers to a value measured according to a method defined in Examples described later. However, the measuring instruments described in the examples are preferable, but it is needless to say that other measuring instruments having the same performance can be similarly measured when the instruments described in the examples are difficult to obtain. The same applies to other measurement methods described later.

<< Composition of composite sheet >>
The composite sheet in the present invention includes a xylylene-based polyamide resin and reinforcing fibers, and the xylylene-based polyamide resin and reinforcing fibers preferably occupy 70% by weight or more of the whole, and more preferably occupy 80% by weight or more of the total. It is particularly preferable to account for 90% by weight or more of the whole.
The lower limit of the proportion of the xylylene-based polyamide resin in the composite sheet in the present invention is preferably 20% by weight or more, and more preferably 25% by weight or more. The upper limit is preferably 60% by weight or less, more preferably 50% by weight or less, and further preferably 48% by weight or less.
The lower limit of the proportion of reinforcing fibers in the composite sheet in the present invention is preferably 40% by weight or more, more preferably 50% by weight or more, and further preferably 52% by weight or more. As an upper limit, it is preferable that it is 80 weight% or less, and it is more preferable that it is 75 weight% or less.

<Xylylene-based polyamide resin>
<< Moisture content of polyamide resin >>
In the present invention, the water content of the xylylene-based polyamide resin measured by the Karl Fischer method is 1% by weight or more and the saturated water content or less. By setting it as such a structure, it becomes easy to impregnate a reinforcing fiber sheet with a xylylene-type polyamide resin. The lower limit of the amount of water is preferably 1.3% by weight or more, more preferably 1.5% by weight or more, still more preferably 1.6% by weight or more, and 1.8% by weight or more. You can also. The upper limit of the water content is preferably 8% by weight or less, more preferably 7% by weight or less, still more preferably 6% by weight or less, still more preferably 5% by weight or less, and still more preferably. Is 4% by weight or less. By setting it as such a range, it exists in the tendency for the effect of this invention to be exhibited more effectively. Details of the amount of water in the present invention are as described in the examples. Further, the saturated water content refers to the saturated water content at 1.01325 bar and 25 ° C.
In the present invention, it is preferable to perform a moisture absorption treatment on the xylylene-based polyamide resin so that the moisture content of the xylylene-based polyamide resin is a predetermined ratio. Examples of the moisture absorption treatment include means such as immersion in water, standing at high temperature, and high humidity.

<< Melting point and glass transition temperature of xylylene-based polyamide resin >>
The melting point of the xylylene-based polyamide resin used in the present invention is preferably 170 ° C. or higher, more preferably 200 ° C. or higher, as the lower limit, from the viewpoint of heat resistance and melt moldability, 330 ° C. or lower is preferable, and 320 ° C. or lower is more preferable.
The glass transition temperature of the xylylene polyamide resin used in the present invention (Tg) of, when the water content of the resin is a glass transition temperature when 0 wt% and a Tg ^0, Tg ⁰ × 0.7 temperatures below The temperature is preferably Tg ⁰ × 0.5 or more and Tg ⁰ × 0.7 or less.
The melting point and glass transition temperature of the xylylene-based polyamide resin in the present invention are values measured by the following method.
“DSC-60” manufactured by Shimadzu Corporation is used, the sample amount is about 5 mg, nitrogen gas is flowed at 30 ml / min as the atmospheric gas, and the temperature rising rate is expected from room temperature at 10 ° C./min. The melting point was determined from the temperature at the peak top of the endothermic peak observed when the mixture was heated to a temperature equal to or higher than the melting point. Next, the melted xylylene-based polyamide resin was rapidly cooled with dry ice, and again heated to a temperature equal to or higher than the melting point at a rate of 10 ° C./min, to obtain a glass transition temperature.

<< Melting viscosity of xylylene-based polyamide resin >>
The melt viscosity of the xylylene-based polyamide resin in the present invention at a melting point of + 35 ° C., a holding time of 6 minutes, and an apparent shear rate of 36.5 s ⁻¹ is preferably 500 Pa · s or less, more preferably 400 Pa · s or less. Preferably, it is 350 Pa · s or less, more preferably 300 Pa · s or less, even more preferably 250 Pa · s or less, even more preferably 200 Pa · s or less, even more preferably 150 Pa · s or less. More preferably, it is s or less. The lower limit value of the melt viscosity is not particularly defined, but can be, for example, 50 Pa · s or more.
The melt viscosity of the xylylene-based polyamide resin in the present invention refers to a value measured according to a method defined in Examples described later.

<< Composition of Xylylene Polyamide Resin >>
The xylylene-based polyamide resin used in the present invention is a polyamide resin containing a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, and 50 mol% or more of the structural unit derived from diamine is derived from xylylenediamine.
As for the structural unit derived from diamine, 70 mol% or more is preferably a structural unit derived from xylylenediamine, more preferably 80 mol% or more is a structural unit derived from xylylenediamine, and 90 mol% or more is xylylenediamine. A structural unit derived from range amine is particularly preferred.
The xylylenediamine may be any of metaxylylenediamine, paraxylylenediamine, and a mixture thereof, but preferably contains at least metaxylylenediamine.

Examples of diamines other than xylylenediamine that constitute the structural unit derived from diamine include tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine. , Dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, aliphatic diamine such as 2,4,4-trimethylhexamethylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis ( Aminomethyl) cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminomethyl) de Examples include alicyclic diamines such as phosphorus and bis (aminomethyl) tricyclodecane, diamines having aromatic rings such as bis (4-aminophenyl) ether, paraphenylenediamine, and bis (aminomethyl) naphthalene. 1 type (s) or 2 or more types can be mixed and used.
When a diamine other than xylylenediamine is used as the diamine component, the proportion is less than 50 mol% of the structural units derived from all diamines, preferably 30 mol% or less, more preferably 1 to 25 mol%. Particularly preferably, it is used in a proportion of 5 to 20 mol%.

The structural unit derived from a dicarboxylic acid is preferably a structural unit derived from an α, ω-linear aliphatic dicarboxylic acid having 50 to 20% by mole and having 4 to 20 carbon atoms, and 70% by mole or more having 4 to 20 carbon atoms. More preferably, it is a structural unit derived from 20 α, ω-linear aliphatic dicarboxylic acid, and 80 mol% or more is a structural unit derived from α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. More preferably, 90 mol% or more is particularly preferably a structural unit derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.
The structural unit derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms is more preferably a structural unit derived from an α, ω-linear aliphatic dicarboxylic acid having 6 to 9 carbon atoms. Specific examples of the α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms include succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid, dodecanedioic acid. Aliphatic dicarboxylic acids such as acids can be exemplified, and one or a mixture of two or more can be used. Among these, the melting point of the xylylene-based polyamide resin is in an appropriate range for molding, so that adipic acid Or sebacic acid is preferable.

Examples of the dicarboxylic acid component other than the α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms include phthalic acid compounds such as isophthalic acid, terephthalic acid and orthophthalic acid, 1,2-naphthalenedicarboxylic acid, 3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3- Examples thereof include naphthalenedicarboxylic acid such as isomers such as naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid.
These dicarboxylic acid components can be used alone or in combination of two or more.

  Furthermore, in addition to the diamine component and the dicarboxylic acid component, as components constituting the xylylene-based polyamide resin, lactams such as ε-caprolactam and laurolactam, aminocaproic acid, aminoundecanoic acid and the like as long as the effects of the present invention are not impaired. Aliphatic aminocarboxylic acids can also be used as copolymerization components.

  As a first embodiment of the xylylene-based polyamide resin used in the present invention, 70 mol% or more of the structural unit derived from diamine is derived from metaxylylenediamine, and 70 mol% or more of the structural unit derived from dicarboxylic acid is adipic acid. And xylylene-based polyamide resin derived from at least one of sebacic acid (more preferably, adipic acid). By setting it as such a structure, it exists in the tendency for gas barrier property to improve.

  As a second embodiment of the xylylene-based polyamide resin used in the present invention, 70 mol% or more of the structural unit derived from diamine is derived from xylylenediamine, and 70 mol% or more of the structural unit derived from dicarboxylic acid is carbon. Derived from α, ω-linear aliphatic dicarboxylic acid and / or isophthalic acid having 4 to 20 atoms, derived from α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms and isophthalic acid The xylylene-type polyamide resin whose molar ratio of the structural unit is 30: 70-100: 0 is illustrated. By adopting such a configuration, the moldability is further improved. When the structural unit derived from isophthalic acid is included, the proportion thereof is preferably in the range of 1 to 30 mol%, particularly preferably 5 to 20 mol% of the structural unit derived from all dicarboxylic acids.

  As a third embodiment of the xylylene-based polyamide resin used in the present invention, in the first or second embodiment, the number-average molecular weight (Mn) of the xylylene-based polyamide resin is 6,000 to 30,000. An example in which 0.5 to 5% by weight of the xylylene-based polyamide resin is a xylylene-based polyamide resin having a molecular weight of 1,000 or less is exemplified.

  By setting the number average molecular weight (Mn) in the range of 6,000 to 30,000, the strength of the composite sheet can be improved. The number average molecular weight (Mn) is preferably 8,000 to 28,000, more preferably 9,000 to 26,000, still more preferably 10,000 to 24,000, and particularly preferably 11,000. ˜22,000, particularly preferably 12,000 to 20,000. Within such a range, heat resistance, elastic modulus, dimensional stability, and moldability are good.

The number average molecular weight (Mn) here is the following from the terminal amino group concentration [NH ₂ ] (μ equivalent / g) and the terminal carboxyl group concentration [COOH] (μ equivalent / g) of the xylylene-based polyamide resin. Calculated by the formula.
Number average molecular weight (Mn) = 2,000,000 / ([COOH] + [NH ₂ ])

Moreover, it is preferable that the xylylene-type polyamide resin in 3rd embodiment contains 0.5-5 weight% of components with a molecular weight of 1,000 or less. By containing such a low molecular weight xylylene-based polyamide resin component in a predetermined range, the impregnation property of the xylylene-based polyamide resin becomes good, and the fluidity between the reinforcing fibers of the xylylene-based polyamide resin becomes good, Generation of voids can be suppressed during the molding process.
The preferred content of the component having a molecular weight of 1,000 or less is 0.6 to 4.5% by weight, more preferably 0.7 to 4% by weight, still more preferably 0.8 to 3.5% by weight. %, Particularly preferably 0.9 to 3% by weight, more preferably 1 to 2.5% by weight.

  The content of the low molecular weight component having a molecular weight of 1,000 or less can be adjusted by adjusting the melt polymerization conditions such as the temperature and pressure at the time of polymerization of the xylylene polyamide resin and the dropping rate of the diamine. In particular, the inside of the reaction apparatus can be depressurized at the latter stage of the melt polymerization to remove low molecular weight components and adjusted to an arbitrary ratio. Further, the low molecular weight component may be removed by hot water extraction of the xylylene-based polyamide resin produced by melt polymerization, or the low molecular weight component may be removed by solid phase polymerization under reduced pressure after the melt polymerization. . In the solid phase polymerization, the low molecular weight component can be controlled to an arbitrary content by adjusting the temperature and the degree of vacuum. It can also be adjusted by adding a low molecular weight component having a molecular weight of 1,000 or less to the xylylene-based polyamide resin later.

  In addition, the measurement of the amount of components having a molecular weight of 1,000 or less is based on a standard polymethyl methacrylate (PMMA) conversion value by gel permeation chromatography (GPC) measurement using “HLC-8320GPC” manufactured by Tosoh Corporation (TOSOH CORPORATION). Can be sought. Two “TSKgel SuperHM-H” were used as the measurement columns, hexafluoroisopropanol (HFIP) having a sodium trifluoroacetate concentration of 10 mmol / l was used as the solvent, the resin concentration was 0.02% by weight, and the column temperature was It can be measured with a refractive index detector (RI) at 40 ° C., a flow rate of 0.3 ml / min. A calibration curve is prepared by dissolving 6 levels of PMMA in HFIP.

The molecular weight distribution (weight average molecular weight / number average molecular weight (Mw / Mn)) of the xylylene-based polyamide resin used in the present invention is preferably 1.8 to 3.1. The molecular weight distribution is more preferably 1.9 to 3.0, still more preferably 2.0 to 2.9. By setting the molecular weight distribution in such a range, a composite material having excellent mechanical properties tends to be easily obtained.
The molecular weight distribution of the xylylene-based polyamide resin can be adjusted, for example, by appropriately selecting the polymerization reaction conditions such as the type and amount of the initiator and catalyst used during the polymerization, and the reaction temperature, pressure, and time. It can also be adjusted by mixing a plurality of xylylene polyamide resins having different weight average molecular weights or number average molecular weights obtained under different polymerization conditions, or by separately precipitating the polymerized xylylene polyamide resins.

  The molecular weight distribution can be determined by GPC measurement. Specifically, using “HLC-8320GPC” manufactured by Tosoh as an apparatus and two “TSK gel Super HM-H” manufactured by Tosoh as columns, eluent trifluoro Measured under conditions of hexafluoroisopropanol (HFIP) having a sodium acetate concentration of 10 mmol / l, a resin concentration of 0.02% by weight, a column temperature of 40 ° C., a flow rate of 0.3 ml / min, and a refractive index detector (RI). It can be determined as a value in terms of methacrylate. A calibration curve is prepared by dissolving 6 levels of PMMA in HFIP.

  The production of the xylylene-based polyamide resin is not particularly limited, and can be performed by any method and polymerization conditions. For example, a salt composed of a diamine component (a diamine such as metaxylylenediamine) and a dicarboxylic acid component (a dicarboxylic acid such as an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms) is added in the presence of water. The xylylene-based polyamide resin can be produced by a method in which the temperature is raised in a pressure state and polymerization is performed in a molten state while removing added water and condensed water. In addition, a diamine component (diamine such as xylylenediamine) is directly added to a dicarboxylic acid component in a molten state (dicarboxylic acid such as an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms), and heavy under normal pressure. A xylylene-based polyamide resin can also be produced by a condensation method. In this case, in order to keep the reaction system in a uniform liquid state, the diamine component is continuously added to the dicarboxylic acid component, and the reaction system is heated up so that the reaction temperature does not fall below the melting point of the generated oligoamide and polyamide. However, polycondensation proceeds.

The composite sheet in the present invention may contain other polyamide resin, an elastomer component, and other additives without departing from the spirit of the present invention. These components are usually added to a polyamide resin composition containing a xylylene-based polyamide resin as a main component. The polyamide resin composition is formed into, for example, a xylylene-based polyamide resin film and used for manufacturing a composite sheet.
Other polyamide resins include polyamide 66, polyamide 6, polyamide 46, polyamide 6/66, polyamide 10, polyamide 612, polyamide 11, polyamide 12, hexamethylene diamine, adipic acid and terephthalic acid polyamide 66 / 6T, hexa And polyamide 6I / 6T made of methylenediamine, isophthalic acid and terephthalic acid. As other resins, aliphatic polyamide resins are preferable, and at least one of polyamide 66 and polyamide 6 is preferable.
In the present invention, the blending amount of the polyamide resin other than the xylylenediamine-based polyamide resin is preferably 5% by weight or less, more preferably 1% by weight or less of the xylylenediamine-based polyamide resin.

  As the elastomer component, for example, known elastomers such as polyolefin elastomers, diene elastomers, polystyrene elastomers, polyamide elastomers, polyester elastomers, polyurethane elastomers, fluorine elastomers, and silicon elastomers can be used. Elastomers and polystyrene-based elastomers. These elastomers include α, β-unsaturated carboxylic acids and their anhydrides, acrylamides and their derivatives in the presence or absence of radical initiators in order to impart compatibility with xylylene-based polyamide resins. A modified elastomer modified with is also preferred.

When the polyamide resin composition contains an elastomer, the blending amount of the elastomer is preferably 5 to 20% by weight of the polyamide resin composition, and more preferably 10 to 15% by weight.
In another embodiment, the polyamide resin composition can be configured to substantially not contain an elastomer. “Substantially free” means, for example, 3% by weight or less of the polyamide resin composition, and further 1% by weight or less.

  Furthermore, the polyamide resin composition used in the present invention is a polyester resin, a polyolefin resin, a polyphenylene sulfide resin, a polycarbonate resin, a polyphenylene ether resin, a polystyrene resin, or the like, as long as the objects and effects of the present invention are not impaired. Multiple blends are possible. These blending amounts are preferably 10% by weight or less of the polyamide resin composition, and more preferably 1% by weight or less.

Furthermore, the polyamide resin composition used in the present invention includes stabilizers such as antioxidants and heat stabilizers, hydrolysis resistance improvers, weather resistance stabilizers, matte materials, and the like within the range that does not impair the objects and effects of the present invention. Additives such as an agent, an ultraviolet absorber, a nucleating agent, a plasticizer, a dispersant, a flame retardant, an antistatic agent, an anti-coloring agent, an anti-gelling agent, a coloring agent, and a release agent can be added. For details of these, reference can be made to the description of paragraph numbers 0130 to 0155 of Japanese Patent No. 4894982, the contents of which are incorporated herein.
In the polyamide resin composition, the xylylenediamine polyamide resin preferably occupies 80% by weight or more, and more preferably 90% by weight or more.

<Reinforcing fiber sheet>
The composite sheet used in the present invention includes a reinforcing fiber sheet. The reinforcing fiber sheet refers to a layered material containing reinforcing fibers as a main component (for example, 90% by weight or more of the total amount is reinforcing fibers), a sheet in which reinforcing fibers are arranged in one direction, a reinforcing fiber fabric, knitted fabric, Nonwoven fabrics are exemplified, and a woven fabric of reinforcing fibers is preferable.
The total basis weight of the reinforcing fiber sheet is preferably 10~10000g / m ^2, more preferably 20~5000g / m ^2, more preferably 50~8000g / m ^2. Here, the basis weight refers to the weight (g) per square meter, and when the reinforcing fiber sheet is treated with the treatment agent as described later, the weight includes the treatment agent.
Moreover, 0.05-10 mm is preferable and, as for the total thickness of a reinforced fiber sheet, 0.1-8 mm is more preferable. Here, the thickness refers to a value measured according to JIS-K 7130. Here, the total thickness means the thickness of one reinforcing fiber sheet when there is one reinforcing fiber sheet, and the total thickness of two or more reinforcing fiber sheets when there are two or more reinforcing fiber sheets. Say it. The thickness of the fiber reinforced sheet can be adjusted by the fineness (number of filaments) of the raw material reinforced fiber and the degree of opening. Further, when the reinforcing fiber sheet is a woven fabric, it can be adjusted by the driving density.
In the present invention, the fibers constituting the fiber reinforced sheet are preferably continuous reinforcing fibers having a fiber length exceeding 10 mm. Although there is no restriction | limiting in particular in the average fiber length of the reinforced fiber used by this invention, It is preferable that it is the range of 1-10,000m from a viewpoint which makes moldability favorable, More preferably, it is 100-10,000m, More preferably, it is 1,000-7,000m.

  Reinforcing fibers include inorganic fibers such as glass fibers, carbon fibers, metal fibers, boron fibers, and ceramic fibers, or aramid fibers, polyoxymethylene fibers, aromatic polyamide fibers, polyparaphenylene benzobisoxazole fibers, and ultrahigh molecular weight polyethylene. Organic fibers such as fibers; and the like, and inorganic fibers are preferable. Among these, carbon fibers and glass fibers are preferably used, and carbon fibers are more preferable because they have excellent characteristics of high strength and high elastic modulus while being lightweight. As the carbon fiber, polyacrylonitrile-based carbon fiber and pitch-based carbon fiber can be preferably used. Moreover, carbon fibers of plant-derived materials such as lignin and cellulose can also be used.

  The reinforcing fiber used in the present invention may be treated with a treating agent. Examples of the treatment agent include a surface treatment agent or a sizing agent. The amount of the treatment agent is preferably 0.001 to 3.0% by weight of the reinforcing fiber, and more preferably 0.1 to 2.0% by weight. By setting it as such a range, the effect of this invention is exhibited more effectively.

Examples of the surface treatment agent include those composed of a functional compound such as an epoxy compound, an acrylic compound, an isocyanate compound, a silane compound, and a titanate compound, such as a silane coupling agent and a titanate cup. Examples of the ring agent include silane coupling agents.
Silane coupling agents include trialkoxy or triallyloxysilane compounds such as aminopropyltriethoxysilane, phenylaminopropyltrimethoxysilane, glycidylpropyltriethoxysilane, methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, and ureido Examples include silane, sulfide silane, vinyl silane, and imidazole silane.

  As the sizing agent, an epoxy resin such as a bisphenol A type epoxy resin, an epoxy acrylate resin having an acrylic group or a methacryl group in one molecule, a bisphenol A type vinyl ester resin, a novolac type vinyl ester resin, Preferred examples include vinyl ester resins such as brominated vinyl ester resins. Further, it may be a urethane-modified resin such as epoxy resin or vinyl ester resin.

  Only one type of treatment agent may be used, or two or more types may be used.

  A well-known method can be employ | adopted for the processing method by the processing agent by a reinforced fiber. For example, the reinforcing fiber is immersed in a liquid (for example, an aqueous solution) containing a treatment agent, and the treatment agent is attached to the surface of the reinforcement fiber. Also, the treatment agent can be air blown on the surface of the reinforcing fiber. Furthermore, you may use the commercial item of the reinforced fiber currently processed with the processing agent, and after washing off the processing agent of a commercial item, you may process again so that it may become a desired quantity.

<Use of composite sheet>
The composite sheet obtained by the production method of the present invention is used as a fiber reinforced resin material, for example, electric / electronic devices such as personal computers, OA equipment, AV equipment, mobile phones, optical equipment, precision equipment, toys, home / office electrical products. It can utilize suitably for components, such as these, housings, and also components, such as a motor vehicle, an aircraft, and a ship.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

<Synthesis Example 1 MPXD10>
In a reaction vessel equipped with a stirrer, a partial condenser, a full condenser, a thermometer, a dropping funnel and a nitrogen introducing tube, and a strand die, 10 kg (49.4 mol) of sebacic acid (TA Grade manufactured by Ito Oil Co., Ltd.) and acetic acid After preparing 11.66 g of sodium / sodium hypophosphite monohydrate (molar ratio = 1 / 1.5) and sufficiently purging with nitrogen, the system was stirred while stirring the system under a small amount of nitrogen. It was heated and melted to 0 ° C.
6.647 kg of mixed xylylenediamine (metaxylylenediamine 34.Mixylylenediamine (Mitsubishi Gas Chemical Co., Ltd.)) and paraxylylenediamine (Mitsubishi Gas Chemical Co., Ltd.) having a molar ratio of 70/30. 16 mol, paraxylylenediamine (14.64 mol) was added dropwise to molten sebacic acid with stirring, and the internal temperature was continuously raised to 240 ° C. over 2.5 hours while discharging the condensed water produced out of the system. Warm up.
After completion of the dropwise addition, the internal temperature was raised, and when the temperature reached 250 ° C., the pressure in the reaction vessel was reduced, and the internal temperature was further raised to continue the melt polycondensation reaction at 255 ° C. for 20 minutes. Thereafter, the inside of the system was pressurized with nitrogen, and the obtained polymer was taken out of the strand die and pelletized to obtain a polyamide resin MPXD10.
The obtained polyamide resin had a melting point of 213 ° C. and a number average molecular weight of 15,400.

<Synthesis Example 2: Synthesis of MXD10>
MXD10 was obtained in the same manner as in Synthesis Example 1 except that the raw material xylylenediamine was all metaxylylenediamine. The melting point was 190 ° C. and the number average molecular weight was 15100.

MXD6: metaxylylene adipamide resin (manufactured by Mitsubishi Gas Chemical, grade S6001), melting point 237 ° C., number average molecular weight 16800

PA6: Polyamide resin 6 (manufactured by Ube Industries, grade 1022B), melting point 220 ° C., number average molecular weight 22000

<Melt viscosity>
The melt viscosity of the polyamide resin at a melting point + 35 ° C., a holding time of 6 minutes, and an apparent shear rate of 36.5 s ⁻¹ was measured by the following method.
As a measuring device, Capillograph D-1 manufactured by Toyo Seiki Co., Ltd., die: diameter 1 mm × 10 mm length was used. For the measurement resin sample, the water absorption was adjusted by allowing the pellets to stand at a normal pressure of 40 ° C. and a relative humidity of 80% for an arbitrary time. Pellets with adjusted water absorption were put into a die and melt viscosity was measured.

<Reinforcing fiber sheet>
Carbon fiber sheet: manufactured by Mitsubishi Rayon, TR3110M, basis weight 200 g / m ² , thickness 1 mm per sheet
Glass fiber sheet: Nittobo, WF 350 100 BS6, basis weight 328 g / m ² , thickness 1 mm per sheet

<Example 1>
<< Manufacture of polyamide resin film >>
A stainless steel counter roll in which polyamide resin dried by a vacuum dryer is melt-extruded by a single-screw extruder having a screw having a diameter of 30 mm, extruded through a T-die having a width of 500 mm, and provided with uneven texture on the surface. Thus, the film was pressed at a roll temperature of 70 ° C. and a roll pressure of 0.4 MPa to form a film having a texture on the film surface.
The average thickness of the obtained polyamide resin film was 100 μm.
The obtained polyamide resin was allowed to stand for 4 hours under normal pressure at 40 ° C. and a relative humidity of 80% to adjust the humidity.

<< Measurement of moisture content of polyamide resin >>
The moisture content of the polyamide resin was measured by the following method.
Using a moisture meter CA200 manufactured by Mitsubishi Chemical Analytech Co., Ltd. and a sample charger VA-236S, 1.0 g is cut out from the conditioned polyamide resin film, the set temperature is set to -5 ° C., and the detection is started. The waiting time was 0 second, the measurement time was 30 minutes, and the moisture content was measured by the Karl Fischer method. As a blank, the water content was measured under the same conditions with respect to a sample amount of 0 g. The moisture content of the sample was calculated according to the following formula.
((Water content of test piece)-(water content of blank)) / (weight of test piece) (wt%)

<< Impregnation >>
The eight xylylene-based polyamide resin films obtained above and seven reinforcing fiber sheets were alternately laminated so that both outer sides were made of polyamide resin, and heated at the temperature, pressure and time shown in Table 1. The composite sheet was obtained by pressing. The thickness of the obtained composite sheet and the ratio of reinforcing fibers in the composite sheet are shown in Table 1.

<< Measurement of impregnation rate >>
The impregnation rate of the obtained composite sheet was measured by the following method.
A 2 cm × 2 cm sheet was cut out from the obtained composite sheet, and a cross-sectional photograph was taken using an X-ray CT-scan (manufactured by Yamato, TDM 1000H-II). For the obtained cross-sectional photograph, a region of the reinforcing fiber impregnated with the thermoplastic resin was selected using image analysis software ImageJ, and the area was measured. The impregnation ratio is the area of the reinforcing fiber sheet constituting the composite sheet that is impregnated with the thermoplastic resin in the section corresponding to the reinforcing fiber sheet located at the center in the cross section perpendicular to the membrane surface / the area taken (unit%). ). When the number of reinforcing fiber sheets constituting the composite sheet is one, the impregnation rate in the portion corresponding to the reinforcing fiber sheet is referred to. When the number of reinforcing fiber sheets constituting the composite sheet is an even number, two sheets located at the center Among the reinforcing fiber sheets, the impregnation rate in a region corresponding to the reinforcing fiber sheet having the lower impregnation rate.
The results are shown in Table 1 below.

<Examples 2 to 5, Comparative Examples 1 and 2>
In Example 1, as shown in Table 1, materials and the like were changed, and others were performed in the same manner. The results are shown in Table 1.

  As is apparent from the above table, composite sheets having a high impregnation rate could be produced by impregnating with a xylylene-based polyamide resin having a predetermined moisture content (Examples 1 to 5). On the other hand, when the water content of the xylylene-based polyamide resin is small, the impregnation rate is inferior (Comparative Example 1). Further, when a polyamide resin other than the xylylene-based polyamide resin was used, the impregnation rate was inferior even for a predetermined moisture content (Comparative Example 2).

Example 6
A polyamide resin film composed of MPXD10 obtained as described above, which was rolled, was allowed to stand for 4 hours under normal pressure at 40 ° C. and a relative humidity of 80%, and then placed on a supply stand. In addition, a roll of carbon fiber sheet was installed on the supply stand. The three roll-shaped polyamide resin films and the two roll-shaped carbon fiber sheets were unwound so as to be alternately laminated, and hot-pressed between a pair of rolls. The line speed was 1 cm / min, and the roll temperature was 290 ° C. on both the upper and lower sides. A stable composite sheet was obtained. The impregnation rate was 95.2%.

Comparative Example 3
It was performed in the same manner as in Example 6 except that the polyamide resin film composed of MPXD10 obtained above and in a roll shape was changed to a polyamide resin film composed of PA6 and in a roll shape. . The polyamide resin films adhered to each other during unwinding, and a stable composite sheet could not be obtained. Since a composite film at a practical level could not be obtained, the impregnation rate could not be obtained.

DESCRIPTION OF SYMBOLS 1 Reinforcing fiber sheet 2 Polyamide resin film 3 Composite sheet 4 Upper roll 5 Lower roll

Claims (14)

A polyamide resin containing a structural unit derived from diamine and a structural unit derived from dicarboxylic acid, wherein 50 mol% or more of the structural unit derived from diamine is derived from xylylenediamine, and the water content measured by Karl Fischer method is 1 weight A method for producing a composite sheet, comprising impregnating a reinforcing fiber sheet with a polyamide resin having a saturated water content of not less than 1%. The method for producing a composite sheet according to claim 1, wherein the polyamide resin is a polyamide resin film. The method for producing a composite sheet according to claim 2, wherein three or more polyamide resin films and two or more reinforcing fiber sheets are alternately laminated and impregnated. The total basis weight of the reinforcing fiber sheet is a 10~10000g / m ^2, the composite sheet manufacturing method according to any one of claims 1 to 3. The manufacturing method of the composite sheet of any one of Claims 1-4 whose total thickness of a reinforcing fiber sheet is 0.05-10 mm. 6. The melt viscosity of the polyamide resin according to any one of claims 1 to 5, wherein the melt viscosity is 500 Pa · s or less under the conditions of a melting point + 35 ° C., a holding time of 6 minutes, and an apparent shear rate of 36.5 s ^−1. A method for producing the composite sheet according to 1. The manufacturing method of the composite sheet of any one of Claims 1-6 whose impregnation rate to the reinforced fiber of the said polyamide resin in the said composite sheet is 90% or more. The manufacturing method of the composite sheet of any one of Claims 1-7 whose ratio of the reinforced fiber in the said composite sheet is 10 to 65 weight%. The method for producing a composite sheet according to any one of claims 1 to 8, wherein the xylylenediamine is metaxylylenediamine, paraxylylenediamine, or a mixture of metaxylylenediamine and paraxylylenediamine. . 10 or more of the structural unit derived from dicarboxylic acid is a structural unit derived from a C4-C20 α, ω-linear aliphatic dicarboxylic acid. A method for producing a composite sheet. The manufacturing method of the composite sheet of any one of Claims 1-9 whose 50 mol% or more of the structural unit derived from dicarboxylic acid is a structural unit derived from sebacic acid. The composite sheet according to any one of claims 1 to 11, wherein the impregnation step includes pressurization at 1 to 6 MPa for 10 to 1000 seconds at a temperature of the melting point of the polyamide resin + 10 ° C to the melting point + 100 ° C. Production method. The manufacturing method of the composite sheet of any one of Claims 1-12 whose thickness of the said composite sheet is 200 micrometers or more and 20 mm or less. The method for producing a composite sheet according to any one of claims 1 to 13, wherein the reinforcing fibers are at least one of carbon fibers and glass fibers.

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