JPS6221369B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a low-odor, translucent flame-retardant laminate. As a measure to make laminates safer, it is widely practiced to make substrates flame retardant, but the odor of laminates has become a problem due to the flame retardance. In particular, halogen-based flame retardants often emit odors during the process of processing laminates, such as when heating resist ink, printing resistor ink, overcoat ink, etc., or when heating during punching, which is a safety and health issue. Low odor properties have come to be strongly desired, as they are undesirable for long-term use. Furthermore, in addition to this, there is a demand for a flame retardant method that does not affect variations in printed resistance values in terms of properties as a laminate. As a measure to reduce odor, there is a method of using inorganic flame retardants such as antimony trioxide instead of using organic flame retardants in the phenolic resin as much as possible, but this significantly impairs the transparency of the laminate. The drawback was that circuit inspection using fluoroscopy during circuit formation was not possible. The inventors of the present invention have conducted various studies in view of the above points, and have found that by using hydrated alumina and phosphate ester together as flame retardants, and by incorporating hydrated alumina into the paper base material, a low-odor and translucent material can be produced. The present invention was completed by successfully developing a flame-retardant laminate. That is, in the present invention, when papermaking the base material, 3 to 30% of the total amount of the base material is
A phenolic resin composition containing 30-89% phenolic resin with a high trifunctional group ratio, 10-50% phosphoric acid ester, and 10-20% polyamide resin is added to a paper base material containing 30% hydrated alumina. This is a method for producing a flame-retardant laminate, which comprises impregnating and drying the prepreg, which is then molded. Hydrated alumina as a flame retardant used in the present invention is inorganic and solid, so if it is added to a phenolic resin, there will be a problem with storage stability. Therefore, it is preferable to use a method in which hydrated alumina is made into a paper base material. The particle size of hydrated alumina is 0.5-70μ, preferably 10μ-30μ
Good. If it is less than 0.5μ, the impregnating property will be poor, and 70
If it exceeds μ, the transparency of the laminate will deteriorate. The content in the paper base material is 3 to 30%, preferably 10 to 20%, based on the total amount of the base material. If it is less than 3%, the flame retardance will not be sufficient, and if it is more than 30%, the impregnation of the phenolic resin composition into the paper base material will be poor, which is not preferable. Kraft paper is better than linter paper in terms of warpage and shrinkage, but kraft paper provides good fixation and yield of hydrated alumina, so a mixture of kraft paper and linter paper is also suitable. , but is not particularly limited. In addition, the phosphoric acid esters include triphenyl phosphate, cresyl diphenyl phosphate,
There are tricresyl phosphate, xylenol diphenyl phosphate, nonylphenyl diphenyl phosphate, etc., but the general formula is [However, R ₁ , R ₂ , R ₃ : H, C ₁ to C ₂₀ alkyl group, l+m+n=3] is preferable. The amount of phosphoric acid ester used is 10-50% compared to 30-89% of phenolic resin.
The phosphorus content of the phenolic resin composition is preferably 1 to 5% (in solid terms). 10% phosphate ester
If it is less than 50%, the flame retardance will not be sufficient even when combined with hydrated alumina, and if it exceeds 50%, it will adversely affect the electrical properties, interlayer bonding strength, etc. of the laminate. Polyamide resins added to phenolic resins are obtained from the reaction of amines such as ethylenediamine, hexamethylenediamine, propylenetetramine, diethylenetetramine, diethylenetriamine, and triethylenetetramine with dimer acids obtained from oleic acid, linoleic acid, linoleic acid, etc. It is something. The amount added is phenolic resin 30~
1 to 20% (solid equivalent) to 89%; if it is less than 1%, the flexibility will be insufficient and punching workability and cutting workability cannot be sufficiently improved, and if it exceeds 20%, interlayer bonding will occur. Insufficient strength, solvent resistance, etc. The phenolic resin with a high trifunctional group ratio used in the present invention includes trifunctional phenol, meta-cresol, meta-tertiary butyl phenol, meta-secondary butyl phenol,
A resol type resin is used in which phenols such as 3,5-xylenol and bisphenol A are reacted with formaldehyde under a basic catalyst. Next, the present invention will be specifically explained with reference to Examples. The paper base material used in this example was made by adding hydrated alumina with a particle size of 0.5 to 70μ to papermaking pulp during or after beating, and stirring it well with a fixing agent or dispersant to uniformly disperse the hydrated alumina. After that, it is made into paper using a Fourdrinier paper machine or the like to make base paper for electrical insulation lamination. Preparation of base paper Hydrated alumina (manufactured by Showa Denko K.K., Higilite H-30) was uniformly dispersed in kraft pulp during the beating process of making base paper for electrical insulation lamination using a Fourdrinier paper machine as shown in the following table. A base paper for lamination was manufactured.

【table】

[Table] Preparation of resin A phenolic resin composition was prepared by mixing a phosphoric acid ester and a polyamide resin with a resol resin obtained by reacting phenol and formalin under an alkali catalyst. Resin 1 Phenol 1200Kg, 37% formalin aqueous solution 1080
Kg and 27 Kg of a 28% ammonia aqueous solution were placed in a reaction vessel and reacted at 100°C for 2.5 hours with stirring. After completion of the reaction, continuous dehydration was carried out under reduced pressure at 70℃, and when the internal temperature reached 90℃, dehydration was stopped, cooled, and 950Kg of cresyl diphenyl phosphate, 120Kg of polyamide resin, and 700Kg of methanol were added, followed by gel time (150℃) for 2 hours. A phenolic resin varnish of 9 seconds was obtained. Example 1 Base paper 1 was impregnated with resin 1 and dried to obtain a prepreg with a resin adhesion amount of 52% and a resin flow of 10%. 8 sheets of this prepreg are stacked together and heated to 175℃.
It was molded for 70 minutes under a pressure of 100 kg/cm ² to obtain a copper-clad laminate with a thickness of 1.6 mm. Examples 2 to 3 Base paper 2 or base paper 3 was impregnated and coated with Resin 1, and the same procedure as in Example 1 was carried out to obtain a 1.6 mm copper-clad laminate. Comparative example Tung oil modified phenolic resin (oil modification amount 20%) 100
A flame-retardant phenolic resin prepared by mixing 15 parts of tetrabromobisphenol A, 5 parts of brominated epoxy resin, and 1 part of phosphorus-containing polyol was impregnated onto linter paper containing 5% antimony trioxide.
A prepreg with a resin adhesion amount of 52% and a resin flow of 10% was obtained, and this was molded to obtain a 1.6 mm copper-clad laminate. The physical properties of these laminates are shown in the table below.

【table】

Claims (1)

[Claims] 1. During papermaking of the base material, 3 to 30% of the total amount of the base material
A phenolic resin composition containing 30-89% phenolic resin with a high trifunctional group ratio, 10-50% phosphoric acid ester, and 1-20% polyamide resin is added to a paper base material containing 30% hydrated alumina. A method for producing a flame-retardant laminate, comprising impregnating and drying the prepreg, which is then molded. 2. The method for producing a flame-retardant laminate according to claim 1, wherein the hydrated alumina has a particle size of 0.5 to 70μ. 3 The phosphorus content of the phenolic resin composition is 1 to 5%
So, the phosphoric acid ester has the general formula [However, R ₁ , R ₂ , R ₃ : H, C ₁ to C ₂₀ alkyl group, l+m+n=3] The method for producing a flame-retardant laminate according to claim 1.