Patent Application
20180304604
The present invention relates to the technical field of laminates, specifically involves a resin composition, especially a thermosetting resin composition and a prepreg, a laminate and a printed circuit board prepared therefrom.
With the rapid development of the electronics industry, electronic products tend to be light, thin, short, high density, security and high functionality, requiring electronic components to have higher signal transmission speed and transmission efficiency, which makes higher performance requirements on the printed circuit board as the carrier. Due to high speed and multi-functionalization of electronic product information processing, the application frequency is continually increased, and 3 GHz or more will gradually become mainstream, therefore, besides maintaining the higher requirements on heat resistance of laminate materials, dielectric constant and dielectric loss value will be required to be lower and lower.
The current traditional FR-4 is difficult to meet the application demand on high frequency and rapid development of electronic products. Meanwhile, the substrate material no longer plays the traditional mechanical support role, and will become together with the electronic components an important way to improve product performances for PCB and designers of terminal manufacturers.
Because high Dk will slow down the signal transmission rate, and high Df will convert the signal partly into heat loss in the substrate material, high-frequency transmission with low dielectric constant and low dielectric loss, especially the development of halogen-free high-frequency plates, has become the focus of copper clad laminate industry.
At present, halogen-containing flame retardants (especially brominated flame retardants) are widely used in polymer flame retardant materials, and play a better flame retardant effect. However, it is concluded after the in-depth study of the fire scene that, although the halogen-containing flame retardant has a better flame retardant effect and a small addition amount, the polymer material containing the halogen-containing flame retardant will produce a lot of toxic and corrosive gas and smoke which suffocate people, thereby being more harmful than the fire itself. As a result, the development of the halogen-free flame retardant printed circuit boards has become a key point in the industry with the formal implementations of the EU Waste Electrical and Electronic Equipment Directive and the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment on Jul. 1, 2006. The CCL manufacturers have launched their own halogen-free flame retardant copper clad laminate.
In order to solve the above-mentioned problems, CN101796132B discloses a composition comprising an epoxy resin, a low molecular weight phenol-modified polyphenylene ether and a cyanate. Such epoxy resin composition has excellent dielectric properties, and is capable of maintaining flame retardancy and has high heat resistance. However, brominated flame retardant is used in the epoxy composition for flame retardancy. Although such composition has excellent comprehensive performance, the flame retardant containing bromine component are easy to cause environmental pollution during the product manufacture, use or even recovery or disposal, and are hard to meet the requirements of the environmental protection.
CN103013110A discloses a cured product comprising a cyanate, allyl benzene-maleic anhydride, a polyphenylene ether, and bismaleimide, and the use of phosphorus-nitrogen compound as flame retardant can achieve low dielectric constant, low dielectric loss, high heat resistance and high flame resistance. However, bismaleimide has a high curing temperature, and the cured product is more brittle, resulting in many deficiencies during the processing and use.
Therefore, it is an urgent problem to be solved how to produce a prepreg and laminate having low dielectric constant, low dielectric loss and excellent chemical resistance.
The present invention aims to provide a resin composition, especially a thermosetting resin composition and a prepreg, a laminate and a printed circuit board prepared therefrom.
In order to achieve the object, the present invention uses the following technical solution.
On one aspect, the present invention provides a thermosetting resin composition comprising the following components in parts by weight: 50-150 parts of a cyanate, 30-120 parts of an epoxy resin, 20-70 parts of allyl benzene-maleic anhydride, 20-100 parts of a polyphenyl ether, 30-100 parts of a halogen-free flame retardant, 0.05-5 parts of a curing accelerator, and 50-200 parts of a filler.
The allyl benzene-maleic anhydride of the present invention has the following chemical structural formula:
wherein x is 1-4, 6 and 8; n is 1-12; x and n are both integers.
In the present invention, the allyl benzene-maleic anhydride is in an amount of 20-70 parts by weight, e.g. 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, and 70 parts by weight.
The present invention adopts allyl benzene-maleic anhydride, which not only makes the substrate have low dielectric constant and dielectric loss, but also increases the heat resistance of the substrate because of the increase of the steric hindrance and the rotational steric hindrance in the molecular chain due to the presence of methyl group. Meanwhile, the hydrophobicity of methyl group can remarkably improve the moisture resistance of the substrate.
The cyanate in the present invention is at least one selected from the group consisting of the following chemical structures:
wherein X1 and X2 are each independently selected from at least one of R, Ar, SO2 and O; R is selected from the group consisting of —C(CH3)2—, —CH(CH3)—, —CH2— and substituted or unsubstituted dicyclopentadienyl; Ar is anyone selected from the group consisting of substituted or unsubstituted benzene, biphenyl, naphthalene, phenolic aldehyde, bisphenol A, bisphenol A phenolic aldehyde, bisphenol F and bisphenol F phenolic aldehyde; n is an integer of greater than or equal to 1; Y is an aliphatic functional group or aromatic functional group.
In the present invention, said cyanate is in an amount of 50-150 parts by weight, e.g. 50, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, or 150 parts by weight.
By adding cyanate, the thermosetting resin composition of the present invention can notably increase the heat resistance and dielectric properties of the system.
The epoxy resin of the present invention is anyone selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol Z type epoxy resin, bisphenol M type epoxy resin, bisphenol AP type epoxy resin, bisphenol TMC type epoxy resin, biphenyl epoxy resin, alkyl novolac epoxy resin, dicyclopentadiene epoxy resin, bisphenol A type novolac epoxy resin, o-cresol type novolac epoxy resin, phenol type novolac epoxy resin, trifunctional epoxy resin, tetrafunctional epoxy resin, isocyanate modified epoxy resin and naphthalene type epoxy resin, or a mixture of at least two selected therefrom.
In the present invention, the epoxy resin is in an amount of 30-120 parts by weight, e.g. 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120 parts by weight.
Due to the introduction of the epoxy resin, the thermosetting resin composition of the present invention can greatly improve the processability.
In the present invention, said polyphenyl ether has a low molecular weight and has a number-average molecular weight of 1000-4000.
In the present invention, said polyphenyl ether is in an amount of 20-100 parts by weight, e.g. 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by weight.
By adding polyphenylene ether, the thermosetting resin composition of the present invention can greatly reduce the dielectric constant and dielectric loss of the plate. In addition, the use of polyphenylene ether can improve the toughness of the plate and have positive influence on the use of the plate in the high-frequency multilayer circuit board.
The halogen-free flame retardant of the present invention is anyone selected from the group consisting of phosphazene, ammonium polyphosphate, tri-(2-carboxyethyl)-phosphine, tri-(isopropylchloro)phosphate, trimethyl phosphate, dimethyl-methyl phosphate, resorcinol bis-xylyl phosphate, phosphorus-nitrogen compounds, melamine polyphosphate, melamine cyanurate, tri-hydroxyethyl isocyanurate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and DOPO-containing novolac resin, or a mixture of at least two selected therefrom.
In the present invention, said halogen-free flame retardant is in an amount of 30-100 parts by weight, e.g. 30, 35, 40, 45, 50, 60, 70, 80, 90, or 100 parts by weight.
The curing accelerator of the present invention is anyone selected from the group consisting of imidazoles, metal salts, tertiary amines or piperidine compounds, or a mixture of at least two selected therefrom.
Preferably, said curing accelerator is anyone selected from the group consisting of 2-methylimidazole, undecyl imidazole, 2-ethyl-4-methylimidazole, 2-phenyl-imidazole, 1-cyanoethyl substituted imidazole, benzyldimethylamine, cobalt acetylacetonate, copper acetylacetonate and zinc isooctanoate, or a mixture of at least two selected therefrom.
In the present invention, said curing accelerator is in an amount of 0.05-5 parts by weight, e.g. 0.05, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 parts by weight.
Preferably, said filler is an inorganic or organic filler.
Preferably, said filler is an inorganic filler, which is anyone selected from the group consisting of aluminum hydroxide, alumina, magnesium hydroxide, magnesium oxide, aluminum oxide, silicon dioxide, calcium carbonate, aluminum nitride, boron nitride, silicon carbide, titanium dioxide, zinc oxide, zirconium oxide, mica, boehmite, calcined talc, talc powder, silicon nitride and calcined kaolin, or a mixture of at least two selected therefrom.
Preferably, said filler is an organic filler, which is anyone selected from the group consisting of polytetrafluoroethylene powder, polyphenylene sulfide and polyethersulfone powder, or a mixture of at least two selected therefrom.
Preferably, said filler has a particle size of 0.01-50 μm, e.g. 0.01 μm, 0.05 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, preferably 1-15 μm, further preferably 1-5 μm.
In order to homogeneously disperse the filler in the resin composition of the present invention, a dispersant may be added in the form of an aminosilane coupling agent or an epoxy silane coupling agent to improve the binding performance between inorganic and woven glass cloth, so as to achieve the purpose of homogeneous dispersion. Moreover, such coupling agent contains no heavy metal, and will not have adverse effects on human bodies. Such coupling agent is in an amount of 0.5-2 wt. % of the inorganic filler. If the amount thereof is too high, it will speed up the reaction and affect the storage time. If the amount thereof is too small, there is no significant effect on the improvement of the bonding stability.
On the second aspect, the present invention provides a prepreg prepared from the thermosetting resin composition as stated in the first aspect of the present invention, wherein said prepreg comprises a matrix material, and the thermosetting resin composition attached thereon after impregnation and drying.
The matrix material of the present invention is a non-woven or woven glass fiber cloth.
On the third aspect, the present invention further provides a laminate comprising the prepreg as stated in the second aspect of the present invention.
On the fourth aspect, the present invention further provides a printed circuit board comprising the laminate as stated in the third aspect of the present invention.
As compared to the prior art, the present invention has the following beneficial effects.
The prepreg and the laminate prepared from the thermosetting resin composition of the present invention have a low dielectric constant which can be controlled below 3.6 and a low dielectric loss which is between 0.0040 and 0.0046, and have excellent flame retardancy, heat resistance, moisture resistance and other comprehensive properties. The flame retardancy thereof can reach the V-0 standard in the flame retardant test UL-94, and the PCT water absorption thereof is 0.29-0.32. They are suitable for the use in halogen-free high-frequency multi-layer circuit boards.
The technical solution of the present invention will be further described below by the specific embodiments.
Those skilled in the art shall know that the examples are merely illustrative of the present invention and should not be construed as specifically limiting the present invention.
Preparation Example: Synthesis of allyl benzene-maleic anhydride
Under the conditions of nitrogen protection and stirring, a maleic anhydride monomer and an initiator were added and dissolved in a medium and heated to 60-80° C. An allyl benzene monomer and a molecular weight regulator were added dropwise. After adding dropwise, the stirring continued for 1-8h to obtain a dispersion system of low molecular weight allyl benzene/maleic anhydride polymer particles, and the dispersion system was centrifuged and dried to obtain a low molecular weight allyl benzene/maleic anhydride alternating copolymer, wherein said initiator was an organic peroxide or azo compound; said medium was a mixed solution of an organic acid alkyl ester and an alkane; said molecular weight regulator was vinyl acetate; maleic anhydride and allyl benzene were in a molar ratio of 1:0.90-0.96; the sum of the mass concentration of two kinds of monomers in the reaction system, maleic anhydride and allyl benzene, was 2.0-7.5%. The mass concentration of the initiator in the reaction system was 0.05-0.35%; the mass concentration of the molecular weight regulator in the reaction system was 0.10-0.45%; the volume fraction of the organic acid alkyl ester in the mixed solution of the organic acid alkyl ester and alkane was 20-80%.
Allyl benzene-maleic anhydride having the following chemical structural formula is obtained:
A cyanate, an epoxy resin, allyl benzene-maleic anhydride, a polyphenylene ether, a halogen-free flame retardant, a curing accelerator, a filler and a solvent were put into a container and stirred to make the mixture uniformly into a glue. The solid content of the solution was adjusted to 60%-70% with the solvent to obtain a glue solution, i.e. a thermosetting resin composition glue solution. A 2116 electronic grade glass cloth was impregnated with the glue, baked into a prepreg by an oven. 6 pieces of 2116 prepregs were covered with electrolytic copper foils having a thickness of 35 μm on both sides, vacuum-laminated in a hot press, cured at 190° C. for 120 min to obtain copper clad laminates.
The components and contents thereof (based on parts by weight) in Examples 1-6 and Comparison Examples 1-5 are shown in Table 1. The component codes and the corresponding component names are shown as follows.
The processes for preparing CCLs in Examples 1-6 and Comparison Examples 1-5 are the same as those in the examples.
The glass transition temperature (Tg), peeling strength (PS), dielectric constant (Dk) and dielectric loss angle tangent (Tg), flame retardancy, dip soldering resistance and water absorption after PCT 2h of the copper clad laminates prepared in Examples 1-6 and Comparison Examples 1-5 were tested by the following methods, and the test results are shown in Table 2.
The performance parameters are tested by the following methods.
The copper clad laminate was immersed in a copper etching solution to remove the surface copper foils, and to evaluate the substrate. The substrate was placed in a pressure cooker and treated at 121° C. and 2 atm for 2 hours. After the water absorption was measured, the substrate was immersed in a tin furnace having a temperature of 288° C. The corresponding time was recorded when the substrate is bubbled or split. The evaluation was finished when the substrate had no foaming or stratification in the tin furnace for more than 5 min.
It can be seen according to the data in Tables 1 and 2 that,
According to Examples 1 to 6, it was found that the laminates prepared by using the thermosetting resin composition of the present invention have a dielectric constant of 3.6 or less, a dielectric loss of 0.0040 to 0.0046, and have excellent flame retardancy, heat resistance, moisture resistance and other comprehensive performances. The flame retardancy thereof can reach the V-0 standard in the flame retardant test UL-94, and PCT water absorption is 0.29-0.32. Thus they are suitable for use in halogen-free high-frequency multilayer circuit boards.
In summary, the thermosetting resin composition of the present invention has a low dielectric constant, low dielectric loss, excellent heat resistance and cohesiveness while ensuring halogen-free flame retardancy, and is suitable for use in halogen-free high frequency multilayer circuit boards.
Certainly, the above-described examples are merely illustrative examples of the present invention and are not intended to limit the implement scope of the present invention. Therefore any equivalent changes or modifications according to the principles within the patent scope of the present invention are all included in the scope of the present patent.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201410633139.X | Nov 2014 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2014/092840 | 12/2/2014 | WO | 00 |
