JPH0496941A - Release sheet and its production - Google Patents

Abstract

PURPOSE:To obtain a release sheet having high releasability from adhesive and heat resistance by subjecting a sheet comprising a specific polyarylene sulfide to stretching heat treatment. CONSTITUTION:A sheet comprising a polyarylene sulfide having 1,000-25,000 poise melt viscosity and a melt crystallization temperature from a temperature 100 deg.C lower than crystal melting point to a temperature 20 deg.C lower than the crystal melting point is melted and extruded from preferably a slit die into a sheetlike state, cooled and solidified on a casting roll at a temperature T( deg.C) satisfying the formula ((t) is thickness of sheet) and subjected to stretching heat treatment below the melting point of the polyarylene sulfide simultaneously with or after cooling and solidification to give the objective sheet having >=15% degree of crystallization.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used, for example, in manufacturing printed circuit boards to protect the adhesive surface exposed by etching from adhering to other surfaces until it is stabilized by curing. The present invention relates to a heat-resistant release sheet that covers an adhesive surface, such as the sheet described above, and a method for manufacturing the same.

[Prior Art] Release sheets are broadly classified into two types: those used as backing materials made of adhesives, adhesives, etc. to protect adhesive surfaces, and those used as process paper.

The most commonly used backing materials are adhesive labels, stickers, and double-sided adhesive tape.

Process paper can be used, for example, in the manufacture of synthetic leather or fine ceramic sheets.1 As a carrier, baking paper is used when baking cakes, cookies, etc., and as a baking tray, it can be used as adhesive exposed by etching on niblint substrates, etc. It is used to protect surfaces from adhesion to other surfaces until they are stabilized by curing.

Conventionally, release sheets used in fields where heat resistance is required include polyvinyl fluoride, FEP (Te1-rafluoroethylene/hexafluoropropylene copolymer), and PFA.
Fluororesins such as (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer) are widely used.

However, polyvinyl fluoride has a temperature of 10% at 170°C.
Some degree of shrinkage is observed, and the heat resistance temperature is said to be around 150°C. FEP and PFA are expensive because they are made from fluorine sources. Polymethylpentene uses a plasticizer when making the sheet, so it comes into contact with the copper in Purine 1 and oxidizes the copper. Also, the heat resistance temperature is 160~1
Since the temperature is 70°C, it cannot be used at high temperatures.

[Problems to be Solved by the Present Invention] An object of the present invention is to provide a release sheet that has heat resistance and good releasability from an adhesive, and a method for manufacturing the same.

The present invention is based on the finding that polyarylene sulfide has excellent releasability from adhesives.

[Means to be solved by the present invention] The present invention will be explained in detail below.

The gist of the present invention is that the melt viscosity is 1,000 to 2.
5.000 poise, melt crystallization temperature is 10 points lower than crystal melting point
This is a release sheet made of polyarylene sulfide having a temperature of 0°C lower to 20°C lower than the crystal melting point and a crystallinity of 15% or more.

Another gist of the present invention is that the melt viscosity is 1.0.
00 to 25,000 poise, and the melt crystallization temperature is 100° C. lower than the crystal melting point to 20° C. lower than the crystal melting point. A sheet made of polyarylene sulfide is subjected to tension heat treatment at a temperature lower than the melting point of the polyarylene sulfide. There is a method of manufacturing a release sheet comprising:

The present invention will be explained in detail below.

The release sheet in the present invention uses polyarylene sulfide alone or a resin composition containing polyarylene sulfide as a main component and blending it with other thermoplastic resins and fillers. Here, the main component refers to 50% by weight or more.

What is polyarylene sulfide in the present invention (-Ar
-3+ (Ar means an arylene group) as a main component. Here 71J-L,
Nji,! = Ha, -Q-, -Q-co-n-, -n-
Refers to an o-isoaromatic compound in which two hydrogen atoms are missing from the aromatic ring, and this aromatic ring may have a substituent. Note that the main component means 50 mol% or more.

The content is preferably 70 mol% or more, more preferably 90 mol% or more.

Other thermoplastic resins include polyolefins such as polyethylene, polypropylene, and poly-4-methylpentene, rubbers such as polyisoprene, fluororesins such as polyethylene terephthalate, polycarbonate, and tetrafluoroethylene resin, polyether 1-thylketone, Polyamide, aromatic polyimides, aromatic polyesters, polystyrene,
Examples include thermoplastic resins such as polyacrylic esters, polymethacrylic esters, polyethernitrile, polyetherketone, polyetherketoneketone, polysulfone, and polyetherimide.

In addition, fillers include glass fiber, aromatic polyamide fiber, carbon black, tarta, clay, titanium oxide,
Contains various organic or inorganic fillers such as mica, molybdenum disulfide, and carbon fiber. These include antioxidant W agents, heat stabilizers, lubricants, and crystallization nucleating agents.

Among these, it is preferable to add a crystallization nucleating agent. Examples of the crystallization nucleating agent include carbon black, silicon oxide, kaolin, clay, and titanium oxide.

The polyarylene sulfide used in the present invention has a melt viscosity of 1,000 to 25,000 poise, preferably 3.0 poise.
00-20,000 voice polyarylene sulfide, preferably a substantially linear high molecular weight polyarylene sulfide. The melt viscosity here refers to the value measured by melt-extruding polyarylene sulfide into pellets at 310°C and a shear rate of 200 sec-'. Also, substantially linear high molecular weight polyarylene sulfide means It refers to a polymer obtained from monomers mainly consisting of difunctional monomers.

Therefore, a small amount of polyhelobenzene may be present as a monomer.

Furthermore, the polyarylene sulfide used in the present invention is
The melt crystallization temperature is 100 °C lower than the crystal melting point to 20 °C lower than the crystal melting point, preferably 90 °C lower than the crystal melting point to 20 °C lower than the crystal melting point, more preferably 80 °C lower than the crystal melting point. ℃ lower temperature to 20℃ lower than the crystal melting point.

The melt crystallization temperature referred to here is determined using a differential scanning calorimeter.
The temperature was raised from 23°C to 380°C at a rate of 10°C/min.
This is the exothermic peak temperature of crystallization that appears when the temperature is lowered at a rate of 10°C/min after being held at 80°C for 3 minutes. In addition, when polyarylene sulfide has two or more melt crystallization temperatures, such as a composition of a block copolymer of polyphenylene sulfide and polyphenylene sulfide ketone, the main peak is defined as the melt crystallization temperature here. do.

In addition, the crystal melting point is measured using a differential scanning calorimeter from 23°C to 1°C.
This is the exothermic peak temperature of crystal melting that appears when the temperature is raised at a rate of 0°C/min. In addition, when polyarylene sulfide has two or more crystal melting points, such as a polymer composition of block copolymer and polyarylene sulfide, the main peak is defined as the crystal melting point here.

Further, the polyarylene sulfide used in the present invention has a crystallinity of 15% or more, preferably 20% or more. Here, crystallinity is defined by creating a density gradient tube,
Density (ρ) and crystal density (ρr) measured at 23°C
, the weight crystallinity (X,) was determined from the amorphous density (ρ) using the following formula.

X(,= (ρ, :/ρ)((ρ−ρ,)/(ρ3.−
ρ, )) The crystal density is determined by calculating the lattice constant using X-ray diffraction, and the amorphous density is determined by actual measurement of a rapidly cooled sample and confirming its amorphous shape using an X-ray diffraction photograph. value is adopted.

The term "sheet" as used in the present invention is a broad concept that also includes thin films. That is, the thickness is not particularly limited, and is usually about 5 to 300 μm.

Among the release sheets according to the present invention, especially those with a crystalline melting point of 2
A material having a heat shrinkage rate of 2% or less in an unrestrained state at a temperature as low as 0° C. is preferably used.

To obtain a sheet made of polyarylene sulfide, the melt viscosity is 1,000 to 25,000 poise, and the melt crystallization temperature is 100°C lower than the crystal melting point to 20°C lower than the crystal melting point. The melt-formed sheet is then heat treated at a temperature below the melting point of the polyarylene sulfide.

Known polymerization methods are employed for polyarylene sulfide, but as described in JP-A-61-7332, an alkali metal sulfide and a dihaloaromatic compound are combined with an organic amide such as N-methylpyrrolidone. It can be suitably obtained by a specific two-step temperature-programmed polymerization method in a solvent in the presence of water. Moreover, a copolymerized polyoctoday aromatic compound containing three or more halogens, such as trichlorobenzene, as a minor component can also be suitably employed.

For forming a polyarylene sulfide sheet, it is preferable to melt and extrude a material made of polyarylene sulfide through a slit-shaped die such as a T-die, cool and solidify it on a casting roll, and crystallize it at the same time or after that. A method of converting the data is adopted. In this case, the resin may be oriented or non-oriented. In general, the resin can be one that has a crosslinked structure and has a high degree of polymerization to provide orientation.

The temperature T ('C) of the casting roll is more than 30°C higher than the glass transition temperature (Tg), but 120°C higher than Tg.
The cooling and crystallization of the sheet is controlled to be within a temperature range of 20°C or higher and within a range that varies depending on the thickness of the sheet, that is, the temperature range defined by the following formula. A stepwise method is preferably employed.

T g+30≦T≦T g+120-0.02
However, t represents the sheet thickness (μm). Tg here again
is the inflection point (°C) when the temperature is raised from 23°C at a rate of 10°C/min using a differential scanning calorimeter.

Further, it is more preferable to use electrostatic application on the casting roll.

If the crystallization in the casting roll is insufficient, it is further subjected to tension heat treatment at a temperature below the melting point, for example, by a method such as dielectric heating. The heat treatment temperature is desirably higher than the temperature at which the release sheet is peeled off. For example, in the case of a release sheet used in the production of flexible printed circuit boards, the temperature is higher than the aging process temperature, and in the case of rigid printed circuit board production, the temperature is higher than the drying process temperature, or higher than the lamination process temperature. Heat resistance can be further improved by such heat treatment. Therefore, when sufficient crystallization is to be achieved all at once using a casting roll, it is particularly recommended to carry out the process at a temperature above the temperature experienced before peeling as described above and below the temperature of T g + 120 - 0.02t (°C). preferable.

In addition to the above-mentioned forming method, a method of melt extrusion, rapid cooling, cold stretching, and tension heat treatment may also be used. However, in the latter method, when the temperature exceeds 210°C, the shrinkage ratio at room temperature after heat treatment relative to the dimension before heat treatment is 2. exceeds %. On the other hand, the former method suppresses the temperature to 2% or less, which is 20° C. lower than the melting point in an unrestricted state, and at the same time has excellent flatness. Therefore, when expansion due to temperature is taken into consideration, the dimensional change value at high temperatures can be further reduced. As a result, the former method is superior to the latter method in that the strain caused by wrapping or the like on the object to be peeled can be made extremely small, and it can be peeled off easily.

(Example) <Measurement method> Peel strength: Using a laminated sheet obtained by the method below, JPCA
Comply with FCOI. In other words, part of the adhesive surface of the laminated sheet is peeled off, one side is fixed to one of the sample holding parts of a tensile tester (Toyo Seiki UTM■ is used), and the other side is attached to the peeled part of the adhesive surface of the laminated sheet. It was bent 180 degrees at the boundary line between the unpeeled part and fixed to the other sample holder of the tensile tester.

The average value of the force required for peeling during peeling when the sample was pulled at a pulling speed of 50 mm/min was calculated.

How to make a laminated sheet: fR foil and adhesive (thickness 35 μm
Film-shaped modified epoxy resin manufactured by Three Bond Co., Ltd.
1650J) were pasted together, passed through a mixing roll with a roll clearance of 450 μm at a speed of 1 m/min at 95°C for temporary adhesion, and then heated at 160°C for 30 minutes for about 30 minutes.
A polytetrafluoroethylene resin sheet was placed on the outside under a pressure of kgf/cm2 and pre-cured by pot pressing, and the polyarylene sulfide sheet shown in the example was laminated on the other side of this adhesive side. ℃, 1 hour, about 30k
Hot pressed under a pressure of g/cm2.

Crystallinity: ρ when measuring crystallinity. The final value is the literature value (Eur
open Polymer Journal, vol.
, 1.4300g/cm from 7.1127 (1971)
”, ρ. is the actual average value of 1, which is the measured average value of various rapidly cooled samples that were confirmed to be amorphous in X-ray diffraction photographs.
3125 g/Cm'' was used.

<Example 1> Polyphenylene sulfide polymerized by a conventional method using 1.36 mol of trichlorobenzene per 100 mol of dichlorobenzene as an aromatic halide was melt-extruded and pelletized. The resulting pellet had a melt viscosity of 16,600 poise, a melt crystallization temperature of 188.2°C, a crystal melting point of 274.6°C, and a glass transition point of 87°C. The obtained pellets were attached to an extruder with a diameter of 35 mm and an L/D of 28, with a lip clearance of 0.55 mm and a width of 2.
Extruded into a sheet shape using a T-die with a 50 mm lip,
It was crystallized while being taken off with a casting roll.

The melting temperature of the resin is 340℃, and the extrusion amount is 3.0kg.
/ It was time. The distance between the tip of the 1-die and the upper end of the casting roll was approximately 10 mm, and the surface temperature of the casting roll was set at 155°C. The diameter of the casting roll was 300 mm.

The resulting sheet has a thickness of 25 μm and a density of 1.3
It was 28 g/cm3 (23°C), and the crystallinity calculated from this value was 18%. The peel strength was 6.5 N when the roll contact surface was used as the peel surface, and 3.2 N when the surface opposite to the roll contact surface was used as the peel surface.

<Example 2> The sheet obtained in Example 1 was further crystallized using a heating roll at 190°C. The density of the sheet is 1.337g/
cm3, and the crystallinity calculated from this value was 27%. Peel strength is 2. When the roll contact surface is the peel surface.
6N, and when the surface opposite to the roll contact surface was used as the peeling surface, it was finished at 2.7N.

<Comparative example> When a commercially available polyvinyl fluoride sheet (thickness: 25μ111) was subjected to the same procedure as in the example, the peel strength was 12.5N when the roll contact surface was the peeling surface, and the peel strength was 12.5N when the roll contact surface was the peel surface. When the surface was used as the peeling surface, the force was 9.3N.

[Effects of the Invention] The present invention provides a sheet that has high releasability to adhesives and is heat resistant.

Claims (4)

[Claims] (1) Made of polyarylene sulfide with a melt viscosity of 1,000 to 25,000 poise, a melt crystallization temperature of 100°C lower than the crystal melting point to a temperature of 20°C lower than the crystalline melting point, and a crystallinity of 15% or more. release sheet (2) The release sheet according to claim 1, which has a thermal shrinkage rate of 2% or less in an unrestrained state at a temperature 20°C lower than the crystal melting point. (3) A sheet made of polyarylene sulfide having a melt viscosity of 1,000 to 25,000 poise and a melt crystallization temperature of 100 °C lower than the crystal melting point to 20 °C lower than the crystal melting point is heated to the melting point of the polyarylene sulfide. A method for producing a release sheet comprising subjecting it to tension heat treatment at a temperature below (4) A sheet made of polyarylene sulfide having a melt viscosity of 1,000 to 25,000 poise and a melt crystallization temperature of 100 °C lower than the crystal melting point to 20 °C lower than the crystal melting point is shaped into slits. The sheet is melt extruded from a die and cooled and solidified on a casting roll at a temperature T (°C) that satisfies the following formula: Tg+30≦T≦Tg+120-0.02t (where t is the thickness of the sheet). A method for producing a release sheet comprising simultaneously or thereafter subjecting the polyarylene sulfide to tension heat treatment at a temperature below the melting point of the polyarylene sulfide.