JPH02283766A - Resin composition - Google Patents

Abstract

PURPOSE:To prepare a lowly dielectric resin compsn. having a flame retardancy, low water absorption, heat resistance, and chemical resistance by compounding a specific thermoplastic resin, porous or hollow particles of a polymer, a reactive flame retardant, and a radical generator. CONSTITUTION:A resin compsn. comprising a crosslinkable thermoplastic resin having a dielectric constant at a frequency of 10<6>Hz and room temp. of 2.7 or lower, porous or hollow particles of a polymer, a reactive flame retardant, and a radical generator. As said crosslinkable thermoplastic resin, a polybutadiene polymer, esp. 1,2-polybutadiene, is pref. because of its high crosslinking efficiency. To obtain a cured product with excellent properties from the compsn., the polybutadiene must contain at least 30wt.% 1,2-vinyl structure and pref. has a number-average MW of 1000-200000.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an electrically insulating low dielectric constant resin composition, and more specifically to a printed wiring having flame retardancy, low water absorption, heat resistance, and chemical resistance. The present invention relates to a low dielectric resin composition suitable for a substrate.

[Prior Art] Polymers made of hydrocarbons are known to have excellent electrical properties, particularly dielectric properties such as low dielectric constant and small dielectric loss tangent, and low water absorption.

Furthermore, among these, cured polymers made of hydrocarbons with a crosslinkable structure have excellent heat resistance and chemical resistance in addition to the above properties, and are used for printing wiring boards, coating resins for printed wiring, and insulation. It has been used in electrical and electronic parts such as varnish.

However, since the constituent elements of these polymers are carbon and hydrogen and are 8 retardant, modern electrical and electronic parts are required to have a certain level of flame retardancy, and flame retardancy is an important factor in developing this field. has become an important issue.

Attempts have been made to add flame retardants to impart flame retardancy, but sometimes it is difficult to impart a sufficient flame retardant effect, and even if flame retardance is achieved, the Excellent dielectric properties are sacrificed.

[Problems to be Solved by the Invention] In order to make a crosslinkable hydrocarbon polymer such as 1,2-polybutadiene flame retardant, hexabromobenzene,
Brominated aromatic compounds such as decabromodiphenyl ether, brominated aromatic polymers such as brominated polystyrene,
Additive flame retardants typified by organic phosphorus compounds such as triphenyl phosphate are added.

In the conventional flame retardant methods described above, it is necessary to add a large amount of flame retardant in order to obtain self-extinguishing properties, and as a result, the excellent dielectric properties and thermal decomposition resistance inherent to hydrocarbon polymers are lost. In addition to impairing heat resistance such as a decrease in heat distortion temperature and heat deformation temperature, they also had drawbacks such as blooming of the flame retardant on the resin surface.

In addition, it is possible to add flame retardant aids such as antimony trioxide, molybdenum oxide, and aluminum hydroxide to reduce the amount of brominated flame retardant compounds used and improve some of the above drawbacks. There were also problems such as the addition of metal compounds impairing the excellent dielectric properties of hydrocarbon polymers.

In order to improve the above drawbacks, reactive flame retardants were added, 1.
Attempts have been made to bond 2-polybutadiene to the polybutadiene skeleton simultaneously with curing.

For example, a derivative having a reactive double bond consisting of 2,4,6-dribromophenyl compound (Japanese Unexamined Patent Publication No. 107-1989)
971) Example of use of a reactive flame retardant consisting of a derivative having 1 to 2 reactive double bonds per molecule derived from a halogenated bisphenol compound (Japanese Patent Publication No. 58-506
66) etc. have been disclosed.

However, these methods do not meet the flame retardant standard UL-9.
Since it is necessary to add a large amount of flame retardant to achieve the v-0 level of 4, it has the effect of preventing flame retardant blooming from the resin surface, which is not achieved with conventional additive flame retardants. - This resulted in a loss of dielectric properties, which is one of the excellent properties unique to polybutadiene.

An object of the present invention is to provide a flame-retardant, low dielectric resin composition that solves the above-mentioned problems.

[Means for Solving the Problems] The low dielectric constant resin composition of the present invention comprises (a) a crosslinkable thermoplastic resin having a dielectric constant of 2.7 or less when measured at 106 hertz, and (b) a porous polymeric resin. The present invention provides a resin composition comprising combined particles or hollow polymer particles (c) a reactive flame retardant and (d) a radical generator.

Examples of the crosslinkable thermoplastic resin (a) having a dielectric constant determined by ΔIII at room temperature of 2.7 or less at a frequency of 108 Hz used in the present invention include polyethylene, polypropylene, ethylene-propylene copolymer, -1,
4-polybutadiene, trans-1,4-polybutadiene, 1,2-polybutadiene, styrene-butadiene random copolymer, block copolymer and hydrogenated products thereof, styrene-isoprene random copolymer, block copolymer and their hydrogenated products, polybutene,
Examples include polyisoprene, butadiene-isoprene copolymer, polypiperine, polyhexene, poly(4-methyl-1-pentene), polystyrene, and polyphenylene oxide.

These can be used alone or in combination of two or more. Among these thermoplastic resins, polybutadiene polymers are preferred from the viewpoint of crosslinking efficiency;
, 2-polybutadiene is particularly preferred because of its excellent crosslinking efficiency.

Furthermore, in order to obtain excellent properties of the thermoset, it is essential that the microstructure contains 30% or more of 1,2-vinyl structure, and the number average molecular weight is 1°000 to 500,000.
00, preferably 1. 000 to 200,000 polybutadiene polymer. Furthermore, depending on the processing method, low molecular weight polybutadiene can be mixed with high molecular weight polybutadiene to reduce melt viscosity and solution viscosity.

The polybutadiene polymers mentioned here include copolymers containing a butadiene component such as butadiene homopolymer, butadiene-styrene copolymer, butadiene-isoprene copolymer, epoxidized polybutadiene with chemically modified polybutadiene skeleton, and maleated polybutadiene. Examples include those having derivative structures such as polybutadiene, terminally hydroxylated polybutadiene, terminally carboxylated polybutadiene, and terminally carboxylic acid esterified polybutadiene.

Among these, butadiene homopolymer, styrene-
Butadiene copolymers are preferred, and butadiene homopolymers are particularly preferred.

In order to maintain the excellent dielectric properties of the resin composition, the dielectric constant of the thermoplastic resin is preferably 2.7 or less, more preferably 2.65 or less.

The particle size of the porous polymer particles (a) of component (b) is determined by the particle size of the seed polymer particles used as seeds,
Usually 0. Preferably, the polymer particles have a narrow distribution width within the range of 1 to 2 μm and have a variation coefficient of particle size distribution of 10% or less.

Further, it is preferable that the porous polymer particles have an average pore diameter of 800 Å or less and a porosity (volume of pores/volume of polymer particles xlOO) of 10 to 90%.

If the particle size of the porous polymer particles is 2 μm or less, there will be no fluctuation in the dielectric constant of the resulting compound, and the porosity will be 1.
When it is 0% or more, the low dielectric effect due to the porosity can be sufficiently exhibited, and when it is 90% or less, it is preferable from the viewpoint of mechanical strength of the polymer particles.

The hollow polymer particles (b) preferably have an outer diameter of 0°05~
10 μm1, more preferably 0.1 to 1 μm1, particularly preferably 0.1 to 0.6 μm1, and the inner diameter is 0.2 to 0.1 μm larger than the outer diameter.
9 times, preferably 0.3 to 0.8 times, particularly preferably 0.
．． It is 5 to 0.75 times.

Such porous polymer particles (a) and hollow polymer particles (b) are manufactured as follows.

The porous polymer (a) is disclosed in Japanese Patent Application No. 63-77689, for example.
As shown in Figure 1, it can be obtained by adding a crosslinking monomer-1 polymerizable monomer and a non-reactive solvent to an aqueous dispersion of seed polymer particles, allowing the seed polymer to absorb these and polymerizing.

The composition of the seed polymer particles is not particularly limited as long as it dissolves or swells in the monomer used for polymerization, but
It is preferable that the polymer be of the same type as the polymer used for polymerization. Specifically, polystyrene and other polymer particles are preferably used.

Usable crosslinking monomers include two or more non-conjugated divinyl compounds such as divinylbenzene, or polyvalent acrylate compounds such as trimethylolpropane tri(meth)acrylate and dipentaerythritol hexaacrylate. A compound having preferably two copolymerizable double bonds can be preferably used.

Examples of the polymerizable monomer include aromatic vinyl compounds such as styrene, vinyl cyanide compounds such as acrylonitrile, (meth)acrylic esters such as MMA, and unsaturated acids such as acrylic acid.

Hollow polymer particles (B) are disclosed in, for example, JP-A-62-1273.
It can be produced by the method shown in No. 36, that is, by utilizing the phase separation and polymerization shrinkage of the polymer inside the particles during polymerization carried out in an aqueous dispersion.

The above-mentioned hollow polymer particles contain 1 to 99 weight percent of a hydrophilic monomer consisting of 1 to 50 weight percent of a crosslinking monomer, 1 to 40 weight percent of an unsaturated carboxylic acid, and/or 5 to 99 weight percent of other hydrophilic monomers. % and other polymerizable monomers that can be copolymerized with the crosslinking monomer or hydrophilic monomer 0 to 85% by weight.
The weight part is a heterogeneous polymer with a composition different from that of the polymer of this polymerizable monomer component (hereinafter simply referred to as "heterogeneous polymer").
) in the presence of 1 to 100 parts by weight, and then polymerizing the polymerizable monomer component.

Examples of the crosslinking monomer include divinyl-based monomers or trivinyl-based monomers such as divinylbenzene, ethylene glycol dimethacrylate, 1゜3-butylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate. Benzene, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate are preferred.

The amount of the crosslinking monomer used is usually 1 to 50 parts by weight, preferably 2 to 50 parts by weight, based on 100 parts by weight of all monomer components.
It is 20 parts by weight.

The hydrophilic monomers include vinylpyridine, glycidyl acrylate, glycidyl methacrylate, methyl acrylate, methyl methacrylate, acrylonitrile, acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide,
Acrylic acid, methacrylic acid, itaconic acid, fumaric acid, sodium styrene sulfonate, vinyl acetate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2
- Vinyl monomers such as hydroxypropyl methacrylate can be exemplified.

The amount of hydrophilic monomer used is usually 10
1 to 99 parts by weight, preferably 5 to 99 parts by weight relative to 0 parts by weight
Parts by weight are preferably in the range of 50 to 95 parts by weight.

Here, when the hydrophilic monomer is an unsaturated carboxylic acid, its proportion is 1 to 40% by weight, preferably 1 to 20% by weight. In addition, the hydrophilic monomer is vinylpyridine, 2
- When using hydroxyethyl methacrylate, it is preferable that m is used within 40% by weight.

Note that a crosslinking monomer with high hydrophilicity, such as ethylene glycol dimethacrylate, glycidyl methacrylate, etc., can be used both as a crosslinking monomer and as a hydrophilic monomer.

If the amount of hydrophilic monomer used is too small, the phase separation of different types of polymers may be insufficient, or different types of polymers may be exposed on the surface of the polymer particles, leading to problems such as uncertain formation of inner pores. arise.

The monomers used as necessary are not particularly limited as long as they have radical polymerizability, and include aromatic vinyl monomers such as styrene and α-methylstyrene, ethylenically unsaturated carboxylic acid alkyl esters, and butadiene. , conjugated diolefins such as isoprene, etc., and styrene is particularly preferred.

The reactive flame retardant (c) that can be used in the present invention is one that is polymerized by a radical source or positively bonded to polybutadiene, and usually has one radically polymerizable carbon-carbon double bond in the molecule. It is a compound containing more than

Specifically, those having the following structure can be mentioned.

In the above formula, R is hydrogen or a methyl group, n is an integer from 0 to 5, and Xm and Xm' may be the same or different and represent a chlorine or bromine substituent.

In addition, m and m' are the number of substituted halogen atoms, 1
It is an integer of ~5.

CH3 " Y is -CH2--CH2-CH2, -CH-m CH3 -C--CH=CH-, etc. carbon number H3 1 to 6 hydrocarbon groups or -3--CO-N 0--C-.

N Among these compounds, brominated compounds are preferred for imparting a flame retardant effect. Particularly preferred compounds include 2
．． 2-bis(4-methacroyloxy-3,5-dibromophenyl)propane, a compound with approximately 2 moles of ethylene oxide added to 1 mole of the above compound, dipromostyrene, tribromostyrene, tribromophenylmaleimide However, in addition to the flame retardant effect, the thermosetting resin obtained is preferable in terms of thermal properties such as heat decomposition resistance and heat distortion temperature.

In addition to being used as a compound formulation, these flame retardants can also be used as monomers constituting the porous fine particles and hollow particles of component (b), or they can be used in combination.

As the curing agent (d) used in the flame-retardant resin composition of the present invention, a radical generator that can be used in a radical crosslinking reaction can usually be used, and a specific example thereof is an organic peroxide. These organic peroxides include dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, 2.5
-dimethyl-2,5-di(t-butylperoxy)-
Hexane, dialkyl peroxide such as 1,3-bis(t-butylperoxyisopropyl)benzene, 1
．． 1-di-t-butylperoxy-3゜3.5-trimethylcyclohexane, 1,1-di-t-butyl-peroxycyclohexane, 2゜2-di(t-butylperoxy)butane, 4.4 Examples include peroxyketals such as -di-t-butyl peroxyvaleric acid n-butyl ester.

The blending weight ratio of components (a), (b), and (c) is preferably 10 to 80/10 to 80/10 to 80, particularly preferably 15 to 60/20 to 70/15 to 60.

The amount of organic peroxide (d) to be used is 0.00 parts by weight per 100 parts by weight of the total amount of the butadiene polymer and the halogen-containing compound.
1 to 10 parts by weight is preferable, more preferably 0.5 to 10 parts by weight.
It is 8 parts by weight.

The flame-retardant low dielectric resin of the present invention can usually be prepared in the following manner.

For example, to impart a certain amount of porous or/and hollow polymer particles, a halogen-containing compound, an organic peroxide, and, depending on the purpose, dimensional stability to a crosslinkable hydrocarbon polymer, a thermosetting resin may be added. Rolls, kneaders, fillers, etc.
After kneading with a kneading device such as a Brabender, a cured product is prepared under predetermined curing conditions.

Alternatively, predetermined amounts of porous or/and hollow polymer particles, specific reactive flame retardants, organic peroxides, and auxiliary materials may be added to a crosslinkable hydrocarbon polymer, such as toluene, xylene, ethylbenzene, n- hexane, n-hebutane,
Varnishes are prepared by dissolving or dispersing them in organic solvents such as cyclohexane, methylcyclohexane, tetrahydrofuran, methylene chloride, chloroform, carbon tetrachloride, and ethane dichloride. A laminate can be obtained by impregnating and drying a cloth or nonwoven fabric, removing the solvent, producing a prepreg, stacking several sheets of the prepreg as necessary, and laminating and molding under predetermined temperature and pressure conditions. Further, at this time, copper foil can be layered on one or both sides of the laminate to form a copper-clad laminate. The flame-retardant low dielectric resin laminate obtained by this method has low water absorption, excellent heat resistance, solvent resistance, and dielectric properties, and is suitable for printed wiring boards due to its excellent flame-retardant properties. Can be used for

Note that the composition of the present invention may contain Si02,
Inorganic fillers such as A 1203 and T i O2 and short fibers such as glass fibers, quartz fibers, and aramid fibers can be added to improve dimensional stability and the like. The amount of these added is 5 parts by weight per 100 parts by weight of the hydrocarbon polymer.
-200 parts by weight is preferred, more preferably 10-1
00 parts by weight.

Alternatively, fabrics or nonwoven fabrics made of inorganic or organic fibers such as glass fibers, quartz fibers, or aramid fibers are layered alternately on the sheet-like compound after kneading, and lamination molding is performed under predetermined temperature and pressure conditions to form a laminate. can be obtained.

Moreover, a composite board or a copper-clad laminate can be made by overlapping copper foil on one or both sides of the cured product obtained at this time.

The substrates and laminates thus obtained have low water absorption, heat resistance, solvent resistance, and low dielectric constant, so they can be suitably used for printed wiring boards with excellent high frequency characteristics.

[Example] The present invention will be specifically explained below using Examples.

Analysis/evaluation method Flame retardant properties Evaluation was made according to the UL-94 standard.

Dielectric properties In accordance with JIS C-6481, the dielectric constant and loss tangent at 25° C. were measured at a frequency of 10 MHz at room temperature.

Solder Heat Resistance Immerse in a solder bath at 260℃ for 30 seconds, and there are no abnormalities such as shape or appearance. 01. Items with abnormalities such as blistering.
And so.

Trichloride resistance According to JIS C-6481, the samples were immersed in trichlorethylene for 5 minutes, and those with no abnormalities in shape and appearance were rated 01, and those with abnormalities were rated x.

Water absorption: The test piece was dried at 100° C. for 4 hours, accurately weighed, and immersed in water at 23° C. for one day. The water adhering to the surface was wiped off, and the water absorption rate was calculated from the weight increase after accurately weighing.

The linear expansion coefficient was measured from room temperature to 100°C by thermal mechanical analysis (TMA).

Example 1 1,2 whose microstructure has 90% of 1,2-vinyl bonds
-Polybutadiene (manufactured by Japan Synthetic Rubber, trade name JSR)
RB810. Number average molecular weight 150.000) 100 parts by weight, polystyrene seed polymer 10 parts by weight, crosslinking monomer divinylbenzene 50 parts, styrene 5
0 parts, non-reactive solvent cyclohexanol 5(1'
50 parts by weight of porous polymer particles obtained by polymerization with an average particle diameter of 1.20 μm and many 0.05 to 0.1 μm pores observed on the particle surface, and 180 parts by weight of tribromophenylmaleimide. , 1.1-di-t-butylperoxy-
After roll kneading 4 parts by weight of 3,3,5-trimethylcyclohexane (manufactured by Kayaku Nouri Aji, trade name: Tribonox 29, purity 75%, calcium carbonate dispersion), it was formed into a sheet, cured at 180°C for 2 hours, and then Post-curing was performed at 200° C. for 2 hours to prepare a cured sheet.

A flame retardant sheet was prepared from the obtained cured product. The results are shown in Table-1.

Example 2 10 parts by weight of polystyrene was used as a seed polymer for synthesizing the porous polymer particles used in Example 1, and 2,2-bis(4-acroyloxy-3,
80 polymerized parts of 5-dibromophenyl)propane, 20 parts by weight of styrene, 5 parts of cyclohexanol as a non-reactive solvent
Average particle size 1.35μ obtained by polymerization using 0 parts by weight
A cured product sheet was prepared in the same manner, except that 100 parts by weight of porous particles with pores of 0.06 to 0.12 μm were observed on the particle surface was used, and the flame retardant was changed to 120 parts by weight of tribromostyrene. . The results are shown in Table-1.

Example 3 10 parts by weight of polystyrene was used as a seed polymer for synthesizing the porous polymer particles used in Example 1, and 2,2-bis(4-acroyloxyethyl-3,5-dibromophenyl) was used as a crosslinking monomer. ) Porous polymer particles were synthesized in the same manner as in Example 1, except that 150 parts by weight of propane (manufactured by Dai-Kogyo Co., Ltd., trade name: GX-6094P) was added. The same process was carried out except that the flame retardant was changed to 100 parts by weight of tribromostyrene for 50 parts by weight of porous polymer particles with an average particle size of 1.45 μm that had pores of 0.05 to 0.14 μm on the particle surface. A cured product sheet was prepared. The results are shown in Table-1.

Example 4 A cured product was prepared in the same manner as in Example 1, except that hollow polymer particles were used instead of the porous polymer particles used in Example 1. The results are shown in Table-1.

Hollow polymer particles were prepared by the following method.

Styrene content 45wt% with average particle size 0.25μm
4 parts by weight of styrene-butadiene copolymer latex (
(2 parts by weight in terms of polymer) were used as seed polymer particles, and 30 parts of a 1% aqueous solution of sodium lauryl sulfate, 20 parts of a 5% aqueous solution of polyvinyl alcohol, and 100 parts of water were uniformly mixed. To this system was added a dispersion in which a mixture of 80 parts by weight of methyl methacrylate, 20 parts of divinylbenzene, 30 parts of toluene, 2 parts of benzoyl peroxide, and a 0.1% sodium lauryl sulfate solution was finely dispersed using an ultrasonic disperser. , slowly stirred for 3 hours to be absorbed into the seed polymer particles, and polymerized for 75 hours and 6 hours until the outer diameter was 1.0 μm.
A hollow particulate polymer having an inner diameter (outer diameter) of 0.5 μm was prepared.

Example 5 80 parts of methyl methacrylate used in the preparation of the hollow particles used in Example 4 was replaced with 40 parts of methyl methacrylate.
A cured product was prepared in the same manner as in Example 1, except that 40 parts of tribromostyrene were used as the reactive flame retardant, and tribromophenylmaleimide was replaced with tribromostyrene as the reactive flame retardant. The results are shown in Table-1.

Comparative Example 1 A cured product was prepared in the same manner as in Example 1 using only 1,2-polybutadiene and a crosslinking agent without using the porous polymer particles used in Example 1 or the reactive flame retardant. The results are shown in Table-1.

Comparative Example 2 A cured product was prepared in the same manner as in Example 1, except that the porous polymer used in Example 1 was not used. Display the results -
Shown in 1.

Blank space below [Effects of the Invention] According to the composition of the present invention, a flame-retardant resin composition that maintains the low dielectric properties inherent to porous polymer particles and hollow polymer particles can be obtained, thereby meeting the requirements for low dielectric properties. It is useful for electrical and electronic component applications.

Patent applicant: Japan Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] (1) (a) A crosslinkable thermoplastic resin having a dielectric constant of 2.7 or less measured at room temperature at a frequency of 10^6 Hertz (b) Porous or hollow polymer particles (c) Reaction A resin composition comprising a flame retardant (d) a radical generator.