JPS6315909B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous method for manufacturing unsaturated polyester resin-based laminates, and in particular to a continuous method for curing the resin.

The present inventors have already disclosed a continuous method for manufacturing a laminate in JP-A-55-4838 or JP-A-55-53013. This allows the heating temperature for curing to be
Although 50°C to 100°C and 50°C to 150°C are known, the present inventor has developed a continuous method for producing unsaturated polyester resin laminates that is superior in product quality and productivity and is more suitable for continuous production of unsaturated polyester resin laminates. As a result of intensive research into new curing methods, we were able to secure a faster curing speed, i.e., production speed, compared to the above known conditions, and were able to proceed with curing sufficiently, making it possible to manufacture products of excellent quality. We found a method and arrived at the present invention.

That is, a plurality of continuously conveyed sheet-like base materials are impregnated with a thermosetting resin liquid that is liquid at room temperature and whose main component is an unsaturated polyester resin, and then the resin-impregnated base materials are continuously laminated. , in a continuous production method of a laminate in which the laminate is continuously heated and cured, after curing in a first heating furnace at an ambient temperature of 60°C or higher and 140°C or lower, the temperature is 190°C at an ambient temperature of 140°C or higher.
This is a method of curing an unsaturated polyester resin laminate, which is post-cured in the following second heating furnace.

The unsaturated polyester resin laminate referred to in the present invention refers to a laminated insulating board or a metal foil-covered laminate for printed circuit boards particularly intended for electrical purposes, but is not limited thereto.

The thermosetting resin liquid which is liquid at room temperature and whose main component is an unsaturated polyester resin as used in the present invention refers to an unsaturated polyester chain and crosslinking whose main ingredients are an unsaturated polybasic acid, a saturated polybasic acid, and a polyhydric alcohol. In addition to the vinyl monomer, other curing catalysts, curing aids, fillers, flame retardants, various stabilizers, modifiers, etc. are mixed as necessary. There is no problem in that the unsaturated polyester chain is a flame-retardant resin containing halogen.

The base material referred to in the present invention is a well-known long sheet-like material such as kraft paper, linter paper, synthetic fiber cloth or non-woven fabric thereof, cloth or non-woven fabric made of glass fiber or glass staple fiber. can be applied to any.

As the vinyl monomer for crosslinking, generally known monomers such as styrene monomer, acrylic esters, methacrylic esters, divinylbenzene, or diallyl phthalate can be used alone or in a mixture of two or more, but price and product Generally, styrene monomer is used because of its characteristic characteristics.

Preferably curing the unsaturated polyester resin is important in manufacturing. The degree of curing can be evaluated by, for example, the heat shrinkage rate of the cured laminate or the amount of residual crosslinking vinyl monomer. In the present invention, a case will be described below in which styrene, which is commonly used as a crosslinking vinyl monomer, is used, but the present invention is not limited thereto.

Now, unsaturated polyester resins are usually cured by heating a resin liquid to which a catalyst such as a peroxide that generates radicals by thermal decomposition is added. The higher the heating temperature is, the more radicals are generated and the curing of the unsaturated polyester resin progresses more rapidly. For example 80-90
The amount of styrene monomer remaining in the cured product cured in an atmosphere of 120°C to 130°C is greater than the amount of styrene monomer remaining in the cured product cured at an ambient temperature of 120°C to 130°C. However, curing at a high ambient temperature is not necessarily effective in sufficiently advancing curing. According to the research of the present inventors, for example, 60~
The amount of residual styrene monomer in the cured product cured for about 10 minutes at an ambient temperature of 140° C., preferably 90 to 140° C., remains in the amount of several percent to several thousand ppm.
Therefore, a second heating furnace was installed and the ambient temperature was 140~140℃.
When post-curing is carried out at 190°C, more preferably at 140-170°C, the amount of residual styrene monomer can be reduced to several tens to hundreds of ppm.
It decreases by a wide margin. The post-curing time is 3 to 20
Minutes are preferred. A heating furnace having an ambient temperature of 60 to 140°C is called a first heating furnace. As already mentioned, the higher the ambient temperature in the first heating furnace, the lower the amount of residual styrene monomer in the product cured by the first heating furnace. For example, when post-curing at 160°C for 10 minutes, the amount of residual styrene monomer in the cured product is:
On the contrary, it increases relatively. That is, the lower the atmospheric temperature of the first heating furnace is, the more the amount of styrene present in the product cured by the first heating furnace increases, but the amount of remaining styrene is significantly reduced by post-curing in the second heating furnace.

If the cured product is cured under conditions where the ambient temperature in the first heating furnace exceeds 140°C, the amount of residual styrene monomer in the cured product will not decrease much even after post-curing. If the atmospheric temperature of the first heating furnace is 60° C. or lower, the curing time generally becomes longer and productivity deteriorates. At this time, a low-temperature decomposition type catalyst can be used for the purpose of improving productivity, but in that case, the pot life of the resin is short, which hinders production and is therefore unsuitable.

A suitable ambient temperature of the second heating furnace is 140 to 190°C. At temperatures below 140°C, the effect of post-curing is small.
That is, the amount of residual styrene decreases little. On the other hand, even if the temperature exceeds 190°C, the rate of decrease in the amount of residual styrene remains the same as at 190°C.

On the other hand, in the present invention, a metal foil-clad laminate can be produced by laminating metal foil or adhesive-coated metal foil and curing the unsaturated polyester resin at the same time as or after laminating the resin-impregnated base materials. However, for example, when the metal foil is copper foil, the ambient temperature of the second heating furnace is 190°C.
If it exceeds this amount, the oxidation discoloration of the copper foil becomes significant.

A feature of the present invention is that after curing in the first heating furnace, curing is further advanced by post-curing in a second heating furnace at a higher temperature. This allows curing to proceed sufficiently even when the production speed is increased.

The invention is further enhanced, for example, by careful selection of the curing catalyst. As the curing catalyst in the present invention, any generally commercially available organic peroxide can be used, but examples include di-t-butyl peroxide, t-butylperoxy-2
-Ethylhexanoate, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, t-butylperoxybenzoate, and other organic peroxides having a decomposition temperature of medium to high temperature are preferred. Among these catalysts, catalysts with a relatively low thermal decomposition temperature such as Perbutyl O (manufactured by NOF Corporation, t-butyl peroxy-2-ethylhexanoate) and catalysts with a relatively high thermal decomposition temperature such as Perbutyl Z
(t-butyl peroxybenzoate manufactured by NOF Corporation), the present invention can be made even more effective. Further, the catalyst with a low thermal decomposition temperature is mainly decomposed by heating in the first heating furnace, and the catalyst with a high thermal decomposition temperature is mainly decomposed during post-curing in the second heating furnace, so that curing can be further promoted. . Now, in the present invention, the first heating furnace for curing is further divided into at least two or more zones, and each of the divided zones can be independently controlled at an ambient temperature between 60 and 140°C. This can be said to be preferable because it allows more appropriate conditions to be set.

As described above, the present invention makes it possible to manufacture a laminate with a small amount of residual styrene monomer and, in other words, a more advanced hardening process, using smaller equipment or with higher productivity.

In the present invention, the first heating furnace and the second heating furnace are installed in succession, and even if heating is performed continuously, there is no deviation from the present invention.
Further, the laminate sent out from the first heating furnace can be cut into regular lengths as necessary, and then post-cured in the second heating furnace.

In the present invention, favorable results can often be obtained by post-curing in the second heating furnace and then further curing by heating, or by exposing to a high-temperature and humid atmosphere.

In the present invention, the amount of residual styrene monomer was determined from a gas chromatogram of an acetone solution extracted at room temperature for about 24 hours.

The drawing is an explanatory diagram of an apparatus showing an example of the continuous curing method for unsaturated polyester resin laminates according to the present invention.The present invention will now be explained based on this explanatory diagram of the apparatus. A single or plural sheet-like base material shown as medium 1 is dried by passing through a drying device 2, and then a thermosetting resin liquid is supplied and impregnated by a resin supplying device 3, and a cover film 4 is coated on the substrate. After that, a resin-impregnated base material is laminated, and this is cured through a first zone 5 and a second zone 6 divided in a first heating furnace controlled at 60 to 140 ° C., and further After peeling off the cover film 4, it is cut, and the cut laminate is sent to a second heating furnace 8 controlled at 140 to 190°C for post-curing, completing the continuous curing of the present invention.

Example 1 0.8 parts of Perbutyl O (manufactured by NOF Corporation) as a catalyst per 100 parts by weight of Polymer 6304 manufactured by Takeda Pharmaceutical Co., Ltd.
Five sheets of continuously conveyed kraft paper (Tomoekawa Paper MKD-150) are each impregnated with an unsaturated polyester resin liquid containing 0.2 parts of Perbutyl H (Nippon Oil & Fats Co., Ltd.), and then laminated, and at the same time the top and bottom are thickened.
It was covered with a 100 μm Mylar film and then introduced into a heating furnace. The styrene monomer concentration of the primary cured product, which was cured by heating at 90°C for 15 minutes in a heating furnace, was approximately 3.5%.
Post-curing at 160°C for 10 minutes reduced the amount of residual styrene monomer to about 74 ppm.

Example 2 The same procedure as in Example 1 was carried out except that the primary curing conditions were changed to 120°C for 10 minutes, and the styrene monomer concentrations in the primary cured product and post-cured product were approximately 3840 ppm and approximately 420 ppm, respectively. Ta.

Comparative Example 1 The same procedure as in Example was carried out except that the primary curing conditions were changed to 150° C. for 5 minutes, and the styrene monomer concentration after post-curing was about 1300 ppm.

Example 3 In Example 2, the heating furnace was divided into two zones, and the temperature of the first zone was set to 135°C, and the temperature of the second zone was set to 135°C.
When the temperature was set to 120°C, the preheating time was shortened by about 2 minutes, and the curing time in the first heating furnace was reduced to about 8 minutes in total, and the post-curing in the second heating oven was performed at 160°C for 10 minutes. The residual styrene monomer concentration was approximately 460 ppm.

[Brief explanation of the drawing]

The drawing shows an example of an apparatus for continuously producing an unsaturated polyester resin laminate according to the present invention. DESCRIPTION OF SYMBOLS 1... Base material, 2... Drying device, 3... Resin supply device, 4... Cover film, 5... First zone, 6... Second zone, 7... First heating furnace, 8
...Second heating furnace.

Claims (1)

[Claims] 1 Impregnating a plurality of continuously conveyed sheet-like base materials with a thermosetting resin liquid that is liquid at room temperature and containing an unsaturated polyester resin as a main component, then continuously laminating the resin-impregnated base materials, and then continuously laminating the resin-impregnated base materials. In the continuous production method of laminates, which are heated and cured, the ambient temperature is
A series of unsaturated polyester resin laminates, characterized in that they are cured in a first heating furnace at a temperature of 60°C or higher and 140°C or lower, and then post-cured in a second heating furnace at an ambient temperature of 140°C or higher and 190°C or lower. Hardening method.