JP2021050446A - Nonwoven fabric, production method of nonwoven fabric, prepreg, printed wiring board and electronic component - Google Patents

Abstract

To provide a nonwoven fabric excellent in heat resistance.SOLUTION: A nonwoven fabric contains a thermoplastic resin A, having a highest melting point in the range of 290°C to 330°C, with a difference between thermal decomposition initiation temperature and the melting point of 80°C or less.SELECTED DRAWING: None

Description

The present invention relates to non-woven fabrics, non-woven fabric manufacturing methods, prepregs, printed wiring boards and electronic components.

Compared with glass cloth, the non-woven fabric is excellent in flexibility, uniformity, denseness and the like from the viewpoint that the fibers constituting the non-woven fabric can be made finer. For this reason, non-woven fabrics have a wide range of uses such as filters such as liquid filters and air filters, sanitary materials, medical materials, agricultural coating materials, earth and wood, building materials, oil adsorbents, automobile materials, separators, clothing, and packaging materials ( For example, see Patent Document 1). In particular, the non-woven fabric has an advantage that it is less likely to be damaged by calendar processing or bending processing and is superior in processing suitability as compared with glass cloth.

Japanese Unexamined Patent Publication No. 2014-24601

However, the conventional non-woven fabric is not excellent in heat resistance, and there is room for improvement. Therefore, an object of the present invention is to provide a non-woven fabric having excellent heat resistance, a method for producing the same, and a prepreg, a printed wiring board, and an electronic component using the non-woven fabric.

Specific means for solving the above problems include the following aspects.

[1] Containing thermoplastic resin A
A non-woven fabric having the highest melting point in the range of 290 ° C. to 330 ° C. and a difference between the thermal decomposition starting temperature and the melting point of 80 ° C. or less.
[2] The non-woven fabric according to [1], which has an average fiber diameter of 3 μm or less.
[3] The non-woven fabric according to [1] or [2], wherein the difference between the melting point and the thermal decomposition start temperature is 30 ° C. or more.
[4] The non-woven fabric according to any one of [1] to [3], which has a yellowness of 6.0 or less.
[5] A value (Dd / Da × 100) obtained by dividing the average fiber diameter (Da) from the standard deviation (Dd) of the average fiber diameter and multiplying by 100 is 40 to 100, [1] to [4]. The non-woven fabric according to any one of.
[6] The non-woven fabric according to any one of [1] to [5], wherein the thermoplastic resin A contains a polyamide.
[7] The non-woven fabric according to [6], wherein the thermoplastic resin A contains a structural unit having an aromatic group.
[8] The polyamide contains structural units derived from one or more aliphatic monomers.
The non-woven fabric according to [6] or [7] _{, wherein the ratio of two} CH groups contained in the polyamide is less than 10, calculated by the following steps (1) to (4).
(1) The number N of the aliphatic monomers contained in the polyamide is specified.
(2) For each of the specified aliphatic monomers, _{the number of CH 2} groups per structural unit derived from the aliphatic monomer is determined.
(3) The total S of the number of the _two CHs contained in the polyamide is calculated.
(4) The total S is divided (S / N) by the number of the aliphatic monomers contained in the polyamide, and this is taken as the ratio of _{two CHs contained in the polyamide.} However, the structural unit derived from the aliphatic monomer refers only to the aliphatic monomer unit in which the content of the polyamide with respect to the total mass is 10% by mass or more.
[9] Using two or more axes,
A resin composition containing a thermoplastic resin A, which has a highest melting point in the range of 290 ° C. to 330 ° C. and a difference between the thermal decomposition start temperature and the melting point of 80 ° C. or less is kneaded. Kneading and melting process to obtain a kneaded melt by melting and
A spinning process in which the kneaded melt is spun together with heated air from a nozzle having a plurality of holes,
A stretching step of stretching the melt spun by the spinning step with the heated air, and a stretching step.
A method for producing a non-woven fabric, including.
[10] The kneading and melting step uses two or more shafts.
At a temperature higher than the highest melting point of the resin composition by 10 ° C. or more and lower than the thermal decomposition start temperature of the resin composition by 5 ° C. or more.
The production method according to [9], which is a step of kneading and melting the resin composition.
[11] The non-woven fabric according to any one of [1] to [8] and
A resin composition containing at least one of a thermosetting resin and a thermoplastic resin,
Prepreg including.
[12] The thermosetting resin is a thermosetting resin having a curing temperature 20 ° C. or more lower than the lowest melting point of the nonwoven fabric.
The thermoplastic resin is a thermoplastic resin having a melting point 20 ° C. or higher lower than the lowest melting point of the nonwoven fabric.
The prepreg according to [11].
[13] A printed wiring board having a conductor layer subjected to wiring processing on one side or both sides of the cured product or solidified product of the prepreg according to [11] or [12].
[14] An electronic component having a circuit for transmitting an electric signal of 1 GHz or higher.
An electronic component in which the insulating layer of the electronic component contains a cured product or solidified product of the prepreg according to [11] or [12].

According to the present disclosure, a non-woven fabric having excellent heat resistance, a method for producing a non-woven fabric, a prepreg, a printed wiring board, and an electronic component are provided.

Hereinafter, embodiments of the present disclosure will be described. These explanations and examples illustrate the embodiments and do not limit the scope of the embodiments.

In the present specification, the numerical range represented by using "~" means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.
In the present specification, the amount of each component in the composition is the total amount of the plurality of substances present in the composition unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition. Means.

In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. .. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

In the present disclosure, the "resin composition" is a concept including a resin alone, and may be a resin alone or a mixture of a resin and other compounds.
In the present disclosure, each component may contain a plurality of applicable substances. When referring to the amount of each component in the composition in the present disclosure, if a plurality of substances corresponding to each component are present in the composition, unless otherwise specified, the plurality of types present in the composition. It means the total amount of substances.
In the present disclosure, the "short fiber" means a fiber having an average fiber length of 200 mm or less. Further, the "long fiber" means a fiber having an average fiber length of more than 200 mm.

≪Non-woven fabric≫
The non-woven fabric has the highest melting point of 290 ° C. to 330 ° C., and is preferably 300 ° C. to 320 ° C. from the viewpoint of making the non-woven fabric more excellent in heat resistance.
The non-woven fabric according to the present disclosure has excellent heat resistance due to the above configuration.

[Non-woven fabric properties]
(Melting point)
The non-woven fabric has the highest melting point of 290 ° C. to 330 ° C., and is preferably 300 ° C. to 320 ° C. from the viewpoint of making the non-woven fabric more excellent in heat resistance.

The highest melting point of the non-woven fabric can be determined as follows.
Using 10 mg of the non-woven fabric as a sample, the sample was (i) heated to 400 ° C. at 100 ° C./min and held at 400 ° C. for 5 minutes, then (ii) cooled to -50 ° C. at 10 ° C./min, and then. (Iii) The highest endothermic peak temperature in the differential scanning calorimetry curve (DSC curve) observed in the second heating process (iii) when the temperature is raised to 400 ° C. at 10 ° C./min. Is the highest melting point of the non-woven fabric. The endothermic peak observed in the differential scanning calorimetry curve (DSC curve) of the second heating process (iii) may be single, and in that case, the observed single endothermic peak temperature may be determined. The highest melting point.

(Pyrolysis start temperature)
From the viewpoint of making the non-woven fabric more excellent in heat resistance, the thermal decomposition start temperature is preferably 330 ° C. to 410 ° C., more preferably 340 ° C. to 400 ° C., and 350 ° C. to 390 ° C. More preferred.

The thermal decomposition start temperature of the non-woven fabric can be obtained as follows.
Using 10 mg of the non-woven fabric as a sample, the sample was subjected to differential thermal analysis (DTA) from 25 ° C. to 450 ° C. at a heating rate of 10 ° C./min under a nitrogen atmosphere, and the temperature when the mass of the sample was decomposed by 1% (DTA). 1% thermal decomposition temperature) is defined as the thermal decomposition start temperature.

(Difference between pyrolysis start temperature and melting point)
The difference between the thermal decomposition start temperature and the highest melting point (= thermal decomposition start temperature-highest melting point) of the non-woven fabric is 80 ° C. or less, and from the viewpoint of making the non-woven fabric superior in heat resistance, it is preferably 70 ° C. or less. , 60 ° C. or lower is more preferable.
The difference between the thermal decomposition start temperature and the highest melting point (= thermal decomposition start temperature-highest melting point) of the non-woven fabric is preferably 30 ° C. or higher, and more preferably 35 ° C. or higher.

(Ultimate viscosity)
From the viewpoint of production, the non-woven fabric preferably has an ultimate viscosity of 0.1 dl / g to 1.0 dl / g, and more preferably 0.2 dl / g to 0.9 dl / g.
The ultimate viscosity [η] of the non-woven fabric is a value measured at 135 ° C. using a decalin solvent. Specifically, it is obtained as follows.
Using 20 mg of a non-woven fabric as a sample, the sample is dissolved in 15 mL of decalin, and the specific viscosity ηsp is measured in an oil bath at 135 ° C. After diluting with 5 mL of decalin solvent added to this decalin solution, the specific viscosity ηsp is measured in the same manner. This dilution operation is repeated twice more, and the value of ηsp / C when the concentration (C) is extrapolated to 0 is obtained as the ultimate viscosity (see the formula below).
[Η] = lim (ηsp / C) (C → 0)

(Melt flow rate)
From the viewpoint of reducing the fiber diameter of the non-woven fabric, the melt flow rate (MFR: ASTM D-1238, 320 ° C., load 2160 g) is preferably 1 g / 10 min to 1000 g / 10 min, and 10 g / 10 min to 500 g / 10 min. Is more preferable.

The method for setting the melting point, the thermal decomposition starting temperature, the difference between the thermal decomposition starting temperature and the highest melting point, the ultimate viscosity or the MFR of the nonwoven fabric within the above ranges is not particularly limited, and for example, the thermoplastic resin A contained in the nonwoven fabric is not limited. (More preferably, the material of the thermoplastic resin A is a method containing polyamide); a method of adjusting the weight average molecular weight of the thermoplastic resin A contained in the non-woven fabric; and the like. Be done.

(Average fiber diameter)
The non-woven fabric preferably has an average fiber diameter of 3 μm or less, more preferably 0.1 μm to 2.0 μm, from the viewpoint of reducing the thickness of the prepreg, the printed wiring board, and the electronic component described later. , 0.5 μm to 1.8 μm, more preferably.

The non-woven fabric is a value obtained by dividing the average fiber diameter (Da) from the standard deviation (Dd) of the average fiber diameter and multiplying it by 100 (Dd / Da × 100) from the viewpoint of improving the filling property when the prepreg is used as described later. However, it is preferably 40 to 100.

The average fiber diameter of the non-woven fabric can be obtained as follows.
The surface of the non-woven fabric to be measured is photographed at a magnification of 1000 times using an electron microscope (model number: S-3500N, manufactured by Hitachi, Ltd.). From the photographed photographs, 100 fibers (n = 100) are arbitrarily selected, the diameter (width) of the selected fibers is measured, and the arithmetic mean value thereof is obtained as the average fiber diameter (Da). The standard deviation (Dd) of the average fiber diameter can be obtained by using the average fiber diameter (Da).

The method of setting the "average fiber diameter" and "(Dd / Da × 100) of the value obtained by subtracting the average fiber diameter (Da) from the standard deviation (Dd) of the average fiber diameter and multiplying by 100" of the non-woven fabric within the above range is Although not particularly limited, for example, the spinning temperature, residence time, nozzle hole diameter, single-hole discharge amount (discharge amount per nozzle hole), temperature of heated air, flow rate of heated air, etc. at the time of manufacturing a non-woven fabric are controlled. There is a method to do it.

(Yellowness: Yellow index)
The non-woven fabric preferably has a yellowness (yellow index) of 6.0 or less from the viewpoint of further improving the durability of the printed wiring board produced by using the prepreg containing the non-woven fabric during long-term use. It is more preferably 9.0 or less, and further preferably 4.0 or less.

The yellowness of the non-woven fabric can be determined in accordance with ASTM D1925.

The specific method for keeping the yellowness of the non-woven fabric within the above range is not particularly limited, but for example, a method for making a non-woven fabric containing a thermoplastic resin A containing polyamide; a method for spinning at a temperature lower than the thermal decomposition start temperature ( Preferably, a method of spinning at a temperature lower than the decomposition temperature by 10 ° C. or more); and the like can be mentioned.

(Tensile strength)
The tensile strength of the non-woven fabric is preferably 5N / 50mm or more, more preferably 5N / 50mm to 200N / 50mm, and even more preferably 10N / 50mm to 100N / 50mm.

The tensile strength of the non-woven fabric can be determined as follows.
A test piece having a width of 50 mm and a length of 200 mm is sampled from the non-woven fabric to be measured, and a tensile tester (Shimadzu Seisakusho Autograph AGS-J) is used to measure the distance between chucks to 100 mm and the head speed to 300 mm / min in the vertical direction (MD direction). ): 5 points, lateral direction (CD direction): 5 points were measured, the average value was calculated, and the tensile strength was determined.

The specific method for setting the tensile strength of the non-woven fabric within the above range is not particularly limited, but for example, a method for using a non-woven fabric containing the thermoplastic resin A containing polyamide; the position of the collector belt to be collected after spinning is brought closer to the nozzle. Method; etc.

(Moisture percentage)
The moisture content of the non-woven fabric can be appropriately determined depending on the intended use, but for example, from the viewpoint of making the conduction characteristics suitable for the prepreg described later, it is preferably small, specifically 1% or less. It is more preferably 0.8% or less, and further preferably 0.5% or less.

The moisture content of the non-woven fabric can be determined as follows.
The moisture content of the non-woven fabric can be determined as the mass loss before and after the heat treatment. Specifically, the mass of the non-woven fabric to be measured is measured with a scale to obtain the mass before treatment. Then, after heating and drying at 120 ° C. for 20 minutes, the mass of the treated nonwoven fabric is obtained by the same measuring method as the mass measurement before the treatment. The mass before and after the obtained treatment is compared, and the amount of mass loss due to the treatment is determined as the water content.

The specific method for keeping the moisture content of the non-woven fabric within the above range is not particularly limited, and examples thereof include a method for making the non-woven fabric containing the thermoplastic resin A containing polyamide.

(Xylene soluble content)
From the viewpoint of long-term reliability when the non-woven fabric is used as a printed wiring board or the like described later, the xylene-soluble content is preferably 5% by mass or less, more preferably 3% by mass or less, and 1% by mass or less. Is more preferable.

The xylene-soluble content of the non-woven fabric can be determined as follows.
1) Weigh 3 g ± 0.2 g of the non-woven fabric to be measured and use this as a sample. The sample is precisely weighed in a 300 mL Erlenmeyer flask, and 100 mL of xylene is added thereto and heated at 120 ° C. for 30 minutes with stirring to completely dissolve the sample.
2) The xylene solution containing the sample is allowed to stand at room temperature (23 ° C.) for 1 hour, and then further allowed to stand in a constant temperature water tank at 25 ° C. for 1 hour.
3) The xylene solution containing the sample is filtered using a filter cloth, the obtained filtrate is placed in a weighed aluminum dish, and the solvent is evaporated to obtain a solid.
4) The aluminum dish containing the solid is vacuum dried at 110 ° C. for 2 hours and allowed to cool in a desiccator.
5) The aluminum dish containing the solid is weighed, and the amount of the solid, that is, the extraction amount is determined.
6) Divide the extraction amount from the weight (weighing amount) of the first sample to obtain the xylene-soluble amount.

The specific method for keeping the xylene-soluble component within the above range in the dissolution test of the non-woven fabric is not particularly limited, but for example, a method for making the non-woven fabric containing the thermoplastic resin A containing polyamide; from the thermal decomposition start temperature of the non-woven fabric. A method of spinning at a temperature lower than 10 ° C.;

(Metsuke)
Basis weight of the nonwoven fabric is be properly determined depending on the ^use, is preferably ^{0.5g / cm 2 ~200g / m 2} , more preferably from ^{1g / m 2 ~100g / m 2} , 1g / m 2 ~ It is more preferably 30 g / m ^2.

The basis weight of the non-woven fabric can be obtained as follows.
Ten test pieces of 100 mm (fiber flow direction: MD) × 100 mm (direction orthogonal to the fiber flow direction (CD direction)) are collected from the non-woven fabric. The test pieces shall be collected at 10 locations in the CD direction. Next, the mass [g] of each of the collected test pieces is measured using a precision electronic balance (manufactured by Kensei Kogyo Co., Ltd.), and the average value of the mass of each test piece is obtained. Calculated from the average value obtained in above 1 m ² per mass [g], the basis weight of the nonwoven fabric [g / m ^2].

The method in which the basis weight of the non-woven fabric is within the above range is not particularly limited, and examples thereof include a method of changing and adjusting the speed of the collector during the production of the non-woven fabric.

(Breathability)
Nonwoven, from the viewpoint of enhancing the impregnation of the thermosetting resin when formed into a prepreg which will be described ^later, it is preferably ^{1cm 3 / cm 2 · sec~200cm 3} / cm 2 · sec, 3cm 3 / cm 2 -Sec to 100 ^{cm 3} / cm ² · sec is more preferable.

The air permeability of the non-woven fabric can be determined as follows.
Prepare a non-woven fabric and in a thermostatic chamber with a temperature of 20 ± 2 ° C and a humidity of 65 ± 2% specified in JIS Z8703 (standard condition of the test site) in accordance with JIS L1096 (8.27.1A method; Frazier type method). Five 20 cm × 20 cm test pieces collected from the non-woven fabric are collected, and the amount of air passing through the test pieces (cm ³ / cm ² · sec) is measured using a Frazier type tester to obtain the average value.

(Thickness)
The thickness of the non-woven fabric can be appropriately determined depending on the intended use, but is preferably 0.01 mm to 100 mm. Further, for example, when used for an electronic material such as a prepreg, the thickness of the non-woven fabric is preferably 0.01 mm to 0.5 mm.

The thickness of the non-woven fabric can be determined as follows.
The thicknesses of the 10 non-woven fabrics to be measured were measured at a total of 5 locations at the center and the four corners, and the average value of the total of 10 locations was calculated. A thickness gauge with a load of 7 gf / cm ² (meter diameter 50 mmφ) was used to measure the thickness.

(length)
The length in the width direction of the non-woven fabric can be appropriately determined depending on the intended use, but is preferably 50 cm or more, and more preferably 100 cm or more.

The length in the width direction of the non-woven fabric can be obtained as follows.
For 10 non-woven fabrics to be measured, the lengths of a total of 3 points at the center and the edge in the width direction were measured, and the average value of each point was calculated. A steel scale was used to measure the length.

[Thermoplastic resin A]
The nonwoven fabric according to the present disclosure contains a thermoplastic resin A.

(Melting point)
The thermoplastic resin A preferably has the highest melting point of 290 ° C. to 330 ° C., more preferably 300 ° C. to 320 ° C., from the viewpoint of forming a non-woven fabric having better heat resistance.

The highest melting point of the thermoplastic resin A can be determined as follows.
Using 10 mg of thermoplastic resin A as a sample, the sample was (i) heated to 400 ° C. at 100 ° C./min, held at 400 ° C. for 5 minutes, and (ii) cooled to -50 ° C. at 10 ° C./min. Then, (iii) when the temperature is raised to 400 ° C. at 10 ° C./min, the highest endothermic peak temperature in the differential scanning calorimetry curve (DSC curve) observed in the second heating process (iii) is determined by thermoplasticity. The highest melting point of the resin A is used. The endothermic peak observed in the differential scanning calorimetry curve (DSC curve) of the second heating process (iii) may be single, and in that case, the observed single endothermic peak temperature may be determined. The highest melting point of the thermoplastic resin A is used.

(Pyrolysis start temperature)
The thermoplastic resin A preferably has a thermal decomposition start temperature of 330 ° C. to 410 ° C., more preferably 340 ° C. to 400 ° C., and 350 ° C. to 390 ° C. from the viewpoint of forming a non-woven fabric having better heat resistance. It is more preferable to have.

The thermal decomposition start temperature of the thermoplastic resin A can be obtained as follows.
Using 10 mg of thermoplastic resin A as a sample, the sample was subjected to differential thermal analysis (DTA) from 25 ° C. to 450 ° C. at a heating rate of 10 ° C./min in a nitrogen atmosphere, and when the mass of the sample was decomposed by 1%. The temperature (1% thermal decomposition temperature) is defined as the thermal decomposition start temperature.

(Difference between pyrolysis start temperature and melting point)
From the viewpoint of making the thermoplastic resin A a non-woven fabric having better heat resistance, the difference between the thermal decomposition start temperature and the highest melting point (= thermal decomposition start temperature-highest melting point) is preferably 80 ° C. or less, preferably 70 ° C. The temperature is more preferably 60 ° C. or lower, and further preferably 60 ° C. or lower.
The difference between the thermal decomposition start temperature and the highest melting point (= thermal decomposition start temperature-highest melting point) of the thermoplastic resin A is preferably 30 ° C. or higher, and more preferably 35 ° C. or higher.

(Ultimate viscosity)
From the viewpoint of production, the thermoplastic resin A preferably has an ultimate viscosity of 0.1 dl / g to 1.0 dl / g, and more preferably 0.2 dl / g to 0.9 dl / g.
The ultimate viscosity [η] of the thermoplastic resin A is a value measured at 135 ° C. using a decalin solvent. Specifically, it is obtained as follows.
Using 20 mg of thermoplastic resin A as a sample, the sample is dissolved in 15 mL of decalin, and the specific viscosity ηsp is measured in an oil bath at 135 ° C. After diluting with 5 mL of decalin solvent added to this decalin solution, the specific viscosity ηsp is measured in the same manner. This dilution operation is repeated twice more, and the value of ηsp / C when the concentration (C) is extrapolated to 0 is obtained as the ultimate viscosity (see the formula below).
[Η] = lim (ηsp / C) (C → 0)

(Melt flow rate)
From the viewpoint of reducing the fiber diameter of the thermoplastic resin A, the melt flow rate (MFR: ASTM D-1238, 320 ° C., load 2160 g) is preferably 1 g / 10 min to 1000 g / 10 min, and 10 g / 10 min to 10 min. More preferably, it is 500 g / 10 min.

The method of setting the melting point, the thermal decomposition start temperature, the difference between the thermal decomposition start temperature and the melting point, the ultimate viscosity or the MFR of the thermoplastic resin A within the above ranges is not particularly limited, and for example, the material of the thermoplastic resin A is used. Examples thereof include a method of using the material described later (more preferably, a method of using the material of the thermoplastic resin A as a material containing polyamide); a method of adjusting the weight average molecular weight of the thermoplastic resin A; and the like.

(Material of thermoplastic resin A)
The thermoplastic resin A is not particularly limited as long as the difference between the melting point and the thermal decomposition start temperature and the melting point satisfies the above-mentioned range, and a known material can be applied.
Examples of the thermoplastic resin A include polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate, syndiotactic polystyrene, cyclic polyolefin, polyphenylensulfide, polytetrafluoroethylene, polysulfone, and polyether sulfone. Examples include amorphous polyarylate, polyetheretherketone, thermoplastic polyimide, polyamideimide, and copolymers thereof. The thermoplastic resin A may be used alone or in combination of two or more.
The thermoplastic resin A preferably contains polyamide from the viewpoint of forming a non-woven fabric having better heat resistance.

Polyamide is a polymer containing at least an amide bond in its structure.
The polyamide may be either a ring-opening polymer of a cyclic amide such as ε caprolactam, a copolymer of a diamine and a dicarboxylic acid, or a mixture thereof.

The polyamide is preferably a copolymer of a diamine and a dicarboxylic acid from the viewpoint of forming a non-woven fabric having better heat resistance.

The diamine preferably contains an aliphatic diamine having 4 to 12 carbon atoms.
Examples of the aliphatic diamine having 4 to 12 carbon atoms include 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, and 1, Linear aliphatic diamines such as 10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane; 2-methyl-1,5-diaminopentane, 2-methyl-1,6-diaminohexane, 2- Branched aliphatic diamines such as methyl-1,7-diaminoheptane, 2-methyl-1,8-diaminooctane, 2-methyl-1,9-diaminononane, 2-methyl-1,10-diaminodecane; and the like can be mentioned. The diamine may be used alone or in combination of two or more.
Among the above, from the viewpoint of forming a non-woven fabric having more excellent heat resistance, the aliphatic diamine having 4 to 12 carbon atoms preferably contains an aliphatic diamine having 6 to 10 carbon atoms, and is linear with 6 to 10 carbon atoms. It is more preferable to contain an aliphatic diamine, and it is further preferable to contain at least one selected from the group consisting of 1,6-diaminohexane, 1,9-diaminononane and 1,10-diaminodecane.

The diamine may contain other diamines (hereinafter, also simply referred to as “other diamines”) other than the aliphatic diamine having 4 to 12 carbon atoms. Examples of other diamines include aromatic diamines such as m-xylylenediamine; and alicyclic diamines such as 1,4-cyclohexanediamine and 1,3-cyclohexanediamine. In this case, the amount of the other diamine is preferably 10 mol% or less with respect to the total number of moles of the aliphatic diamine having 4 to 12 carbon atoms.

The dicarboxylic acid preferably contains at least terephthalic acid, isophthalic acid and an aliphatic dicarboxylic acid having 4 to 10 carbon atoms.
Examples of the aliphatic dicarboxylic acid having 4 to 10 carbon atoms include chain aliphatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, and sebacic acid.

The dicarboxylic acid may contain other dicarboxylic acids (hereinafter, also simply referred to as “other dicarboxylic acids”) other than the terephthalic acid, isophthalic acid and the aliphatic dicarboxylic acid having 4 to 10 carbon atoms. Examples of other dicarboxylic acids include aromatic dicarboxylic acids such as 2-methylterephthalic acid and naphthalenedicarboxylic acid; frangicarboxylic acids; alicyclic dicarboxylic acids such as 1,3-cyclohexanedicarboxylic acid; and fats having 11 or more carbon atoms. Group dicarboxylic acids; and the like. In this case, the amount of the other carboxylic acid is preferably 5 mol% or less with respect to the total number of moles of the terephthalic acid, isophthalic acid and the aliphatic dicarboxylic acid having 4 to 10 carbon atoms.

From the viewpoint of making a non-woven fabric having superior heat resistance, the dicarboxylic acid accounts for 100 mol% of the total number of moles of terephthalic acid, isophthalic acid and an aliphatic dicarboxylic acid having 4 to 10 carbon atoms, and the ratio of terephthalic acid is 35 to 50 mol. %, Isophthalic acid ratio is 25-40 mol% (more preferably 30-40 mol%), and aliphatic dicarboxylic acid having 4-10 carbon atoms is 15-35 mol% (more preferably 20-30 mol%). It is preferably mol%).

Polyamide has a structure derived from an aliphatic diamine having 4 to 12 carbon atoms, a terephthalic acid, an isophthalic acid, and an aliphatic dicarboxylic acid having 4 to 10 carbon atoms in all structural units from the viewpoint of making a non-woven fabric having excellent heat resistance. The total amount of the units is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass or more.

The polyamide preferably contains a structural unit derived from one or more aliphatic monomers from the viewpoint of forming a non-woven fabric having better heat resistance. The aliphatic monomer is not particularly limited as long as it is an aliphatic monomer, and may be, for example, any of the above-mentioned cyclic amide, diamine or dicarboxylic acid. For example, examples of the aliphatic monomer include an aliphatic monomer having 4 to 12 carbon atoms.

The polyamide contains a structural unit derived from one or more kinds of aliphatic monomers from the viewpoint of improving the filling property when it is used as a prepreg, which will be described later, and is calculated by the following steps (1) to (4). _{The ratio of the two} CHs contained is preferably less than 10, more preferably 8 or less, and even more preferably 6 or less.
(1) The number N of the aliphatic monomers contained in the polyamide is specified.
(2) For each of the specified aliphatic monomers, _{the number of CH 2} groups per structural unit derived from the aliphatic monomer is determined.
(3) The total S of the number of the _two CHs contained in the polyamide is calculated.
(4) The total S is divided (S / N) by the number N of the aliphatic monomers contained in the polyamide to obtain the ratio of _{2 CHs contained in the polyamide.} However, the structural unit derived from the aliphatic monomer refers only to the aliphatic monomer unit in which the content of the polyamide with respect to the total mass is 10% by mass or more.

The thermoplastic resin A preferably contains a structural unit having an aromatic group from the viewpoint of forming a non-woven fabric having better heat resistance. The aromatic group is not particularly limited, but is preferably an aromatic group having 5 to 14 carbon atoms, more preferably an aromatic group having 6 to 10 carbon atoms, and an aromatic group having 6 carbon atoms. That is, it is more preferably a phenyl group.

The ratio of the thermoplastic resin A to the entire non-woven fabric is preferably 95% by mass or more, more preferably 98% by mass or more, and 99% by mass or more from the viewpoint of making the non-woven fabric more excellent in heat resistance. Is even more preferable.

[Other ingredients]
The non-woven fabric according to the present disclosure contains antioxidants, heat-resistant stabilizers, weather-resistant stabilizers, antistatic agents, slips, as necessary, as other components other than the thermoplastic resin A, as long as the heat resistance of the non-woven fabric is not impaired. It may contain various known additives such as agents, antistatic agents, lubricants, dyes, pigments, natural oils, synthetic oils, waxes, fatty acid amides and the like. When the non-woven fabric is used for a prepreg, a printed wiring board, and an electronic component described later, it is preferable that the content of these additives in the non-woven fabric is small from the viewpoint of long-term reliability of the circuit board and the like, specifically, 0.1 mass. % Or less is preferable, 0.05% by mass or less is more preferable, and 0.01% by mass or less is further preferable.

(Aspect of non-woven fabric)
The non-woven fabric according to the present disclosure may be either a long-fiber non-woven fabric or a short-fiber non-woven fabric. The nonwoven fabric according to the present disclosure can be produced by, for example, a spunbond method, a melt blown method, a flash spinning method, a wet method, a card method, an airlaid method, an electrostatic spinning method, or the like.

From the viewpoint of productivity, the non-woven fabric according to the present disclosure is preferably a long-fiber non-woven fabric.
The long-fiber non-woven fabric is preferably a non-woven fabric produced by the spunbond method (that is, a spunbond non-woven fabric) or a non-woven fabric produced by the melt-blown method (that is, a melt-blown non-woven fabric). In particular, from the viewpoint of reducing the average fiber diameter, the non-woven fabric is preferably a melt-blown non-woven fabric.

The nonwoven fabric according to the present disclosure may be a single layer or a laminated body in which a plurality of layers are laminated. As the laminated body, the non-woven fabric according to the present disclosure may be contained in at least one layer of the laminated body, and for example, even a laminated body in which a plurality of non-woven fabrics produced by one manufacturing method are laminated. Often, it may be a laminated body in which a plurality of non-woven fabrics produced by two or more kinds of manufacturing methods are laminated, or may be laminated with a layer other than the non-woven fabric such as a film. Examples of the non-woven fabrics and films other than those disclosed in the present disclosure to be laminated include conventionally known non-woven fabrics and films.

≪Use of non-woven fabric≫
The use of the non-woven fabric according to the present disclosure is not particularly limited, and can be used for known uses as the use of the non-woven fabric. Specific examples of applications include prepregs, filters, masks, sanitary goods, packaging materials, and the like. Among these, the non-woven fabric according to the present disclosure is preferably used as a prepreg because it has excellent heat resistance.

≪Manufacturing method of non-woven fabric≫
The method for producing a non-woven fabric according to the present disclosure is a resin composition containing a thermoplastic resin A using two or more shafts, having a highest melting point in the range of 290 ° C. to 330 ° C., and starting thermal decomposition. A kneading and melting step of kneading and melting a resin composition having a difference between the temperature and the melting point of 80 ° C. or less to obtain a kneaded melt, and spinning to spin the kneaded melt together with heated air from a nozzle having a plurality of holes. It includes a step and a stretching step of stretching the melt spun by the spinning step with the heated air.
The method for producing a non-woven fabric according to the present disclosure can produce a non-woven fabric having excellent heat resistance by including the above steps.

(Melting and kneading process)
In the melt-kneading step, the resin composition containing the thermoplastic resin A using two or more shafts has the highest melting point in the range of 290 ° C. to 330 ° C., and the thermal decomposition start temperature and the melting point. The resin composition having a difference of 80 ° C. or less is kneaded and melted to obtain a kneaded melt.

In the kneading and melting step, two or more shafts are used from the viewpoint of producing a non-woven fabric having better heat resistance.
It is preferable that the step is to knead and melt the resin composition at a temperature higher than the highest melting point of the resin composition by 10 ° C. or more and lower than the thermal decomposition start temperature of the resin composition by 5 ° C. or more.
More preferably, the step is a step of kneading and melting the resin composition at a temperature higher than the highest melting point of the resin composition by 15 ° C. or more and lower than the thermal decomposition start temperature of the resin composition by 5 ° C. or more. ,
It is more preferable that the step is a step of kneading and melting the resin composition at a temperature higher than the highest melting point of the resin composition by 20 ° C. or more and lower than the thermal decomposition start temperature of the resin composition by 5 ° C. or more. ..

By using two or more shafts in the kneading and melting step, uneven kneading of the resin composition is unlikely to occur, and kneading can be performed with high accuracy.

The number of shafts in the kneading and melting step is 2 or more, preferably 2 to 10. The shaft refers to a shaft used for kneading, and examples thereof include a screw and the like. The kneading and melting step may be performed using, for example, a melt extruder equipped with two or more screws.

Examples of the thermoplastic resin A in the method for producing a nonwoven fabric according to the present disclosure include the same embodiments as those preferred for the thermoplastic resin A in the nonwoven fabric according to the present disclosure.
Preferred embodiments of the resin composition include the same embodiments as those mentioned in the thermoplastic resin A according to the present disclosure.
Examples of the components other than the thermoplastic resin A in the resin composition include the same embodiments as those preferred for the other components in the nonwoven fabric according to the present disclosure.

The time for kneading and melting the resin composition, that is, the residence time can be appropriately designed according to the production scale and the like, but is preferably 5 minutes to 30 minutes, more preferably 7 minutes to 20 minutes.

(Spinning process)
In the spinning step, the kneaded melt is spun together with heated air from a nozzle having a plurality of holes. Specifically, pressure is applied by an extruder to supply the melt to the spinneret on which the nozzle is formed, and the melt is ejected from the nozzle. The extruder is not particularly limited, and may be a single-screw extruder or a multi-screw extruder. The hole diameter of the nozzle is preferably 0.06 mm to 0.50 mm, more preferably 0.10 mm to 0.30 mm. The discharge amount per hole (single hole discharge amount) in the nozzle is preferably 0.01 g / min to 0.50 g / min, more preferably 0.10 g / min to 0.30 g / min. The temperature of the heated air is preferably 250 ° C to 350 ° C. The flow rate of the heated air ^is preferably ^{200Nm 3 / h / m~800Nm 3 /} h / m.

(Stretching process)
In the stretching step, the melt spun in the spinning step is stretched with heated air. By setting the flow rate, temperature, and flow rate of the heated air within the high-temperature and high-speed range as described above, the average fiber diameter of the melt-blown nonwoven fabric is small, and the generation of resin particles is reduced.

After the stretching step, the fibers fibrillated by high-temperature and high-speed air are collected on a complement plate (for example, a porous belt or a porous drum) and deposited to obtain a non-woven fabric.

The non-woven fabric obtained by collecting and depositing on the collection plate may be further subjected to secondary processing. Examples of the secondary processing include entanglement processing, pressing processing, gear processing, printing processing, coating processing, laminating processing, heat treatment, shaping processing, hydrophilic processing, water repellent processing, press processing and the like.

Examples of the entanglement treatment include heat embossing treatment, ultrasonic fusion treatment, water jet treatment, hot air through treatment, needle punch treatment and the like.

From the viewpoint of maintaining a better balance between rigidity and breathability, the entanglement treatment preferably includes a thermal embossing treatment.
When the non-woven fabric of the present disclosure is thermocompression-bonded by thermocompression bonding, the embossed area ratio (thermocompression bonding portion) is preferably in the range of 5% to 30%, more preferably in the range of 5% to 20%. .. Examples of the engraved shape include a circle, an ellipse, an oval, a square, a rhombus, a square, a square, a quilt, a lattice, a turtle shell, and a continuous shape based on these shapes.

From the viewpoint of controlling the thickness, rigidity, denseness, air permeability, etc. of the non-woven fabric of the present disclosure, it is preferable that the secondary processing includes pressing processing. The pressing means for pressing the non-woven fabric of the present disclosure in the pressing process is not particularly limited, but for example, the pressing means for pressing by applying pressure in the thickness direction of the nonwoven fabric (in the case of a laminated body of non-woven fabric, the laminating direction of the laminated body). It may be. Examples of the pressing process include a method of press-molding two or more layers of non-woven fabric (more preferably melt-blown non-woven fabric) deposited in a sheet shape; roll molding in which the non-woven fabric is pressed by a roll; among these, roll molding. Is preferably included.

≪Prepreg≫
The prepreg according to the present disclosure includes a non-woven fabric according to the present disclosure and a resin composition containing at least one of a thermosetting resin and a thermoplastic resin. Since the prepreg according to the present disclosure contains a resin composition containing the non-woven fabric according to the present disclosure, it is excellent in heat resistance when made into a cured product or a solidified product.

The prepreg according to the present disclosure is cooled at room temperature (23 ° C.) or a cured product obtained by heating at 145 ° C. for 10 minutes and heat-curing from the viewpoint of making the prepreg having better heat resistance when it is made into a cured product or solidified product. The coefficient of thermal expansion of the solidified product at 50 ° C. to 100 ° C. is preferably 50 ppm / ° C. or lower, and more preferably 40 ppm / ° C. or lower.

The prepreg according to the present disclosure preferably has a dielectric loss tangent value of 0.005 or less at 1 GHz when used as a cured product, preferably 0.001 or less, from the viewpoint of being more excellent when used as an insulating layer in a printed wiring board described later. Is more preferable.
The method of setting the value of the dielectric loss tangent within the above range is not particularly limited, and examples thereof include a method of reducing the water content; a method of reducing the fiber diameter.

The method for producing the prepreg is not particularly limited, and a known production method can be applied. For example, as a method for producing a prepreg, a step of impregnating a non-woven fabric containing a resin composition with a non-woven fabric according to the present disclosure to obtain an impregnated body and a step of heating the obtained impregnated body to remove a solvent contained in the varnish. Examples thereof include a manufacturing method including a step of drying.
The impregnation of the varnish containing the above resin composition into the non-woven fabric according to the present disclosure can be carried out, for example, by applying a predetermined amount of varnish to a spray coating method, a dip coating method, a roll coating method, a curtain coating method, a die coating method, a slit coating method, or the like. It can be carried out by applying it to the non-woven fabric according to the present disclosure by a known method, further laminating a protective film on it if necessary, and pressing it from above with a roller or the like.
The method of heating the impregnated body to dry the solvent contained in the varnish is not particularly limited. For example, a batch method of drying in an air atmosphere or a nitrogen atmosphere with a blower dryer, or a continuous process of drying through a heating furnace. How to do it.

Examples of the thermosetting resin include epoxy resin, melamine resin, phenol resin, unsaturated polyester resin, silicone resin and the like. Among the above, the thermosetting resin preferably contains an epoxy resin. The thermosetting resin may be used alone or in combination of two or more. The curable resin is preferably a thermosetting resin having a curing temperature 20 ° C. or more lower than the lowest melting point of the non-woven fabric from the viewpoint of forming a prepreg having excellent heat resistance when it is made into a cured product.

Examples of the thermoplastic resin include the same thermoplastic resins as those exemplified in the above-mentioned thermoplastic resin A. The thermoplastic resin may be used alone or in combination of two or more. The thermoplastic resin is preferably a thermoplastic resin having a melting point 20 ° C. or higher lower than the lowest melting point of the nonwoven fabric, from the viewpoint of forming a prepreg having excellent heat resistance when solidified.

The thickness of the prepreg can be appropriately selected according to the intended use.
The thickness of the prepreg is preferably 0.001 mm to 10 mm, preferably 0.005 mm to 1 mm, from the viewpoint of improving the shapeability when laminating the prepreg, the mechanical strength of the cured product, the toughness, and the like. More preferably, it is more preferably 0.01 mm to 0.5 mm.

The use of the prepreg according to the present disclosure is not particularly limited, but can be used, for example, for a printed wiring board or the like described later.

≪Conductor tension laminate≫
The conductor tension laminate according to the present disclosure is a laminate in which a conductor layer is laminated on at least one surface of the prepreg according to the present disclosure. Since the conductor tension laminate according to the present disclosure has the above structure, it is excellent in heat resistance.
The conductor layer is not particularly limited as long as it is a layer containing a conductive material, but a metal foil is preferable. Examples of the metal leaf include copper foil, aluminum night, nickel night, gold leaf, silver night, stainless steel night and the like. The metal-clad laminate according to the present disclosure can be produced by a known production method.

≪Printed circuit board≫
The printed wiring board according to the present disclosure has a conductor layer in which wiring processing is performed on one side or both sides of the cured product of the prepreg according to the present disclosure. Since the printed wiring board according to the present disclosure has the above configuration, it has excellent heat resistance.

The printed wiring board may have a mode in which a conductor layer subjected to wiring processing is provided on one side or both sides of a laminate formed by laminating a cured product of the prepreg according to the present disclosure.

The printed wiring board may have a conductor layer in which an antenna circuit is processed on one side or both sides of the cured product of the prepreg according to the present disclosure.

The method for manufacturing the printed wiring board is not particularly limited, and a known manufacturing method can be applied. For example, in the method for manufacturing a printed wiring board, the prepreg manufactured by the above-mentioned method is heat-cured by a laminated press or the like to form an insulating layer. Next, the conductor layer is laminated on the obtained insulating layer by a known method to prepare a laminated body. After that, a printed wiring board can be obtained by circuit-processing or the like on the conductor layer in the laminated body.

As the conductor layer, metal is suitable. As the metal, metals such as copper, aluminum, nickel, gold, silver and stainless steel can be used. Examples of the method for forming the conductor layer include a method of forming a conductive substance such as metal into a foil and heat-sealing it to the insulating layer; a method of adhering the insulating layer and the conductor layer using an adhesive; spatter, vapor deposition, and plating. A method of forming a conductor layer by means of the like; and the like. The printed wiring board may be either a single-sided plate or a double-sided plate.
The printed wiring board according to the present disclosure can be used as an electronic component by mounting an electronic component such as a semiconductor element, for example.

≪Electronic parts≫
The electronic component according to the present disclosure is an electronic component having a circuit for transmitting an electric signal of 1 GHz or higher, and the insulating layer of the electronic component includes a cured product of the prepreg according to the present disclosure. The electronic component according to the present disclosure has excellent heat resistance due to the above configuration.
Electronic components can be manufactured based on known information.
Examples of electronic components having a circuit for transmitting an electric signal of 1 GHz or higher include a high-frequency antenna circuit, a backplane such as a high-speed server and a router; and a flexible substrate for high-speed transmission used for a hard disk, a liquid crystal display, and the like.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples. The materials, amounts used, proportions, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present disclosure. Unless otherwise specified, "part" means "part by mass".

-Preparation of materials-
-Polypropylene homopolymer manufactured by ExxonMobil, Achieve 6936G2
MFR: 1550g / 10 minutes, glass cloth Nitto Boseki Co., Ltd., glass cloth for printed wiring boards, IPC spec 1017

Thermoplastic Resin A: Synthesis of Semi-Aromatic Polyamide Resin 1906 g (11.5 mol) of terephthalic acid, 2800 g (24.1 mol) of 1,6-hexanediamine, 1271 g (7.6 mol) of isophthalic acid, 699 g of adipic acid (4.8 mol), 36.5 g (0.3 mol) of benzoic acid, 5.7 g of sodium hypophosphate-hydrate (0.08% by weight based on the raw material) and 545 g of distilled water. It was placed in a 13.6 L autoclave and replaced with nitrogen. The internal temperature of this autoclave was raised from 190 ° C. to 250 ° C. over 3 hours with stirring. At this time, the internal pressure of the autoclave was increased to 3.03 MPa. After continuing the reaction for 1 hour as it was, the atmosphere was released from the spray nozzle installed in the lower part of the autoclave, and then the low condensate was extracted. The extracted low condensate was cooled to room temperature (23 ° C.), pulverized with a pulverizer to a particle size of 1.5 mm or less, and dried at 110 ° C. for 24 hours. The water content of the obtained low condensate was 4100 ppm, and the ultimate viscosity [η] was 0.15 dl / g. Next, this low-condensation product was placed in a shelf-stage solid-phase polymerization apparatus, substituted with nitrogen, and then heated to 180 ° C. over about 1 hour and 30 minutes. Then, the reaction was carried out for 1 hour and 30 minutes, and the temperature was lowered to room temperature (23 ° C.). The ultimate viscosity [η] of the obtained polyamide was 0.20 dl / g. Then, in a twin-screw extruder having a screw diameter of 30 mm and L / D = 36, melt polymerization was carried out at a barrel set temperature of 330 ° C. and a screw rotation speed of 200 rpm at a resin supply rate of 10 kg / h to semi-fragrance as thermoplastic resin A. A group polyamide copolymer was obtained.

[Example 1]
(Making non-woven fabric)
The materials shown in Table 1 were put into a twin-screw kneading extruder via a hopper and melt-kneaded at 340 ° C. so as to have a residence time of 10 minutes. Then, the melt-kneaded material was discharged in a fibrous form together with heated air (340 ° C., 300 Nm ^{3 / h / m) blown from both sides of the nozzle.} At this time, the conditions were a spinning temperature of 340 ° C., a nozzle cap with a hole diameter of 0.20 mmφ, and a single hole discharge amount of 0.15 g / min. Then, the discharged fibrous material was collected in the form of a web to obtain the meltblown non-woven fabric of each example.

(Making prepreg)
Bisphenol A type epoxy resin (trade name: JER828, manufactured by Mitsubishi Chemical Corporation) and 1-benzyl-2-phenylimidazole (Curesol 1B2PZ, manufactured by Shikoku Kasei Co., Ltd.), which are thermosetting resins, are dissolved in a toluene solvent. A resin varnish was obtained. Then, this resin varnish was impregnated with the non-woven fabric of each example and dried in a blower dryer at 145 ° C. for 10 minutes to obtain a cured product of a prepreg having a thickness of 0.3 mm.

(Manufacturing of copper-clad laminate)
Eight prepregs of each example cut into 150 mm squares were stacked, and copper foils (manufactured by Furukawa Electric Co., Ltd., F1-WS) were further laminated on both ends in the stacking direction. Next, copper-clad laminates to which copper foil was adhered were produced by heating with a vacuum press at a pressure of 3.5 MPa and 200 ° C. for 2 hours.

[Comparative Example 1]
A cured product of a prepreg having a thickness of 0.3 mm was obtained in the same manner as in Example 1 except that the above glass cloth was used instead of the non-woven fabric.

[Comparative Example 2]
A cured product of a prepreg having a thickness of 0.3 mm was obtained in the same manner as in Example 1 except that the material and manufacturing method of the non-woven fabric were changed to the following specifications.

(Making non-woven fabric)
The materials shown in Table 1 were put into a twin-screw kneading extruder via a hopper and melt-kneaded at 230 ° C. so as to have a residence time of 10 minutes. Then, the melt-kneaded material was discharged into a fibrous form together with heated air (280 ° C., 300 Nm ^{3 / h / m) blown from both sides of the nozzle.} At this time, the conditions were a spinning temperature of 230 ° C., a nozzle cap with a hole diameter of 0.20 mmφ, and a single hole discharge amount of 0.15 g / min. Then, the discharged fibrous material was collected in the form of a web to obtain the meltblown non-woven fabric of each example.

Table 1 shows the properties of the obtained melt-blown non-woven fabrics of each example. In the table, "-" means that the material cannot be measured and has not been measured. Each property was measured by the measurement method described above.

-Evaluation-
(1) dimensional stability before and after dimensions curing of the prepreg, i.e., in the preparation of the prepreg, the state of not hardened is impregnated with the resin varnish of the examples containing a resin varnish and dimensions S _B of the nonwoven fabric, after curing compared with the size _{S a} prepreg was determined the dimensional change rate _{(%) (= S B /} S a × 100). The dimensional stability was evaluated by applying the dimensional change rate to the following evaluation criteria. The results are shown in Table 1.
<Evaluation criteria>
G1: The dimensional change rate was 5% or less.
G2: The dimensional change rate exceeded 5% and was 15% or less.
G3: The dimensional change rate exceeded 15%.

(2) Fillability The time required to impregnate the non-woven fabric of each example with the resin varnish during the preparation of the prepreg was measured, and the fillability was evaluated according to the following evaluation criteria. The time required for impregnation is the time required from the impregnation of the non-woven fabric of each example to the resin varnish until the unimpregnated portion and the air bubbles that can be visually confirmed disappear.
G1: It was less than 1 minute.
G2: 1 minute or more and less than 5 minutes.
G3: It was not completely impregnated for more than 5 minutes or naturally.

(3) Voids The copper-clad laminates of each example were cut in the thickness direction, and the cut surface was magnified 1000 times with a scanning electron microscope to image 10 locations, and the presence or absence of voids was evaluated according to the following criteria. ..
G1: No voids were observed on the observation surface.
G2: One void was observed on the observation surface,
G3: Ten or more voids were observed on the observation surface.

(4) Processing resistance The non-woven fabric or glass cloth of each example was subjected to calender processing (3 MPa, 130 ° C., speed 1 m / min), and the thickness of the non-woven fabric or glass cloth of each example was measured before and after the calender processing. Then, the bending resistance was evaluated based on the following evaluation criteria.
G1: The thickness after processing is 50% or less of the thickness before processing, and no destruction of the material is observed. G2: The thickness after processing is 50% or less of the thickness before processing, and the material Destruction was observed G3: The thickness after processing exceeded 50% of the thickness before processing, and the material was observed to be destroyed.

As shown in Table 1, the cured product of the prepreg produced using the non-woven fabric of the example is superior in heat resistance to the cured product of the prepreg produced using the non-woven fabric of the comparative example or the glass cloth. all right.

Claims (14)

Contains thermoplastic resin A
A non-woven fabric having the highest melting point in the range of 290 ° C. to 330 ° C. and a difference between the thermal decomposition starting temperature and the melting point of 80 ° C. or less. The nonwoven fabric according to claim 1, wherein the average fiber diameter is 3 μm or less. The non-woven fabric according to claim 1 or 2, wherein the difference between the melting point and the thermal decomposition start temperature is 30 ° C. or more. The non-woven fabric according to any one of claims 1 to 3, wherein the yellowness is 6.0 or less. Any of claims 1 to 4, wherein the value (Dd / Da × 100) obtained by dividing the average fiber diameter (Da) from the standard deviation (Dd) of the average fiber diameter and multiplying by 100 is 40 to 100. The non-woven fabric according to item 1. The non-woven fabric according to any one of claims 1 to 5, wherein the thermoplastic resin A contains a polyamide. The nonwoven fabric according to claim 6, wherein the thermoplastic resin A contains a structural unit having an aromatic group. The polyamide contains structural units derived from one or more aliphatic monomers.
The non-woven fabric according to claim 6 or 7 _{, wherein the ratio of 2} CH groups contained in the polyamide is less than 10, calculated by the following steps (1) to (4).
(1) The number N of the aliphatic monomers contained in the polyamide is specified.
(2) For each of the specified aliphatic monomers, _{the number of CH 2} groups per structural unit derived from the aliphatic monomer is determined.
(3) The total S of the number of the _two CHs contained in the polyamide is calculated.
(4) The total S is divided (S / N) by the number of the aliphatic monomers contained in the polyamide, and this is taken as the ratio of _{two CHs contained in the polyamide.} However, the structural unit derived from the aliphatic monomer refers only to the aliphatic monomer unit in which the content of the polyamide with respect to the total mass is 10% by mass or more. With two or more axes,
A resin composition containing a thermoplastic resin A, which has a highest melting point in the range of 290 ° C. to 330 ° C. and a difference between the thermal decomposition start temperature and the melting point of 80 ° C. or less is kneaded. Kneading and melting process to obtain a kneaded melt by melting and
A spinning process in which the kneaded melt is spun together with heated air from a nozzle having a plurality of holes,
A stretching step of stretching the melt spun by the spinning step with the heated air, and a stretching step.
A method for producing a non-woven fabric, including. The kneading and melting step uses two or more axes,
At a temperature higher than the highest melting point of the resin composition by 10 ° C. or more and lower than the thermal decomposition start temperature of the resin composition by 5 ° C. or more.
The production method according to claim 9, which is a step of kneading and melting the resin composition. The non-woven fabric according to any one of claims 1 to 8.
A resin composition containing at least one of a thermosetting resin and a thermoplastic resin,
Prepreg including. The thermosetting resin is a thermosetting resin having a curing temperature 20 ° C. or more lower than the lowest melting point of the nonwoven fabric.
The thermoplastic resin is a thermoplastic resin having a melting point 20 ° C. or higher lower than the lowest melting point of the nonwoven fabric.
The prepreg according to claim 11. A printed wiring board having a conductor layer subjected to wiring processing on one side or both sides of the cured product or solidified product of the prepreg according to claim 11 or 12. An electronic component having a circuit for transmitting an electric signal of 1 GHz or higher.
An electronic component in which the insulating layer of the electronic component contains a cured product or solidified product of the prepreg according to claim 11 or 12.