JP3085484B2 - Release film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release film, and more particularly, to a film useful as a carrier sheet in cast molding of a ceramic sheet, a urethane sheet or the like.

[0002]

2. Description of the Related Art Conventionally, paper-based release paper occupies most of the release field, but recently, as a substrate other than paper, a polypropylene film, a polyester film,
Plastic films such as polyethylene films have come to be used, satisfying demands for diversifying functions and upgrading products.

[0003] In particular, recently, it has been studied as a carrier sheet at the time of cast molding of a ceramic sheet, a urethane sheet, or the like (Japanese Patent Laid-Open No. 2-252225).
issue). For example, as a method of forming a ceramic, there is a method of laminating and forming a green sheet obtained by thinly applying a ceramic slurry to a carrier film using a doctor blade or the like and removing a solvent. In this method, if the flatness of the green sheet or the unfired ceramic sheet obtained by peeling the carrier film from the green sheet is poor, the properties of the final product obtained by laminating, firing, and processing are deteriorated. Properties, heat resistance and releasability are important properties.

[0004] The polyester film has good flatness, and the releasability can be slightly improved by providing a layer made of a silicone compound, a fluorine compound or a wax on the surface.

[0005] However, since the polyester film has insufficient heat resistance, low temperature conditions must be used for removing the solvent from the ceramic slurry, so that it takes a long time, and water or organic solvents cannot be used. There is a problem that only a specific solvent can be selected due to insufficient resistance.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned disadvantages of the conventional release film, to provide a green sheet having good heat resistance, good water and solvent resistance and good flatness, and It is to provide a release film having good releasability from a green sheet.

[0007]

According to the present invention, there is provided a polyphenylene sulfide film having a coating layer made of a silicone resin on at least one surface of a polyphenylene sulfide film.
The release film is characterized in that the heat shrinkage at 100 ° C. for 30 minutes is 0.3% or less.

[0008] The polyphenylene sulfide (hereinafter abbreviated as PPS) in the present invention is mainly composed of poly-p-phenylene sulfide, and preferably contains at least 70 mol% of p-phenylene sulfide units. More preferably, 90 mol% or more is a p-phenylene sulfide unit. If such units are less than 30 mol%, for example,

Embedded image Although such a component may be contained as a copolymer component, the content of the copolymer component is more preferably 10 mol% or less. In particular,

Embedded image The content of the polyfunctional copolymer component having three or more functional units such as is preferably 2 mol% or less.

The melt viscosity of the PPS of the present invention is 300 ° C.
50 ° C. and an apparent shear rate of 200 sec ⁻¹
The range of 0 to 12000 poise is preferable, and 700 to 70
00 poise is more preferred.

In the present invention, as the PPS film,
An unstretched sheet, a uniaxially stretched film and a biaxially stretched film are exemplified, but a biaxially stretched film is preferable.

The PPS film of the present invention may contain usual additives such as an antioxidant, a heat stabilizer, a lubricant, a crystal nucleating agent, an ultraviolet absorber, a weathering agent and a coloring agent. In particular, it is preferable to include a lubricant such as inorganic or organic particles in order to form projections on the film surface and impart slipperiness. Examples of the particles include silica, calcium carbonate, calcium phosphate, titanium oxide, kaolin, talc, alumina, and zinc oxide. The surface roughness Ra of the PPS film is preferably 0.1 μm or less,
0.07 μm is more preferred.

In the present invention, the silicone resin is a partially crosslinked product of an organic polysiloxane, and the organic chain bonded to the siloxane unit is an alkyl group, an aryl group or a fluoroalkyl group, Groups are preferred. The metal catalyst used for curing may be contained. Further, like the PPS film, the coating layer of the silicone resin may contain inorganic or organic particles for forming the surface. Further, the coating layer may also contain waxes.

The surface of the coating layer in the present invention preferably has a surface roughness Ra of 0.1 μm or less,
7 μm is more preferred. The thickness of the coating layer is preferably 0.01 to 10 μm on at least one side.

The release film of the present invention has a temperature of 100.degree.
Min heat shrinkage is 0.3% or less. Preferably 0.2
5% or less, more preferably 0.2% or less. If the heat shrinkage exceeds 0.3%, the flatness of a green sheet is impaired, which is not preferable.

Next, a method for producing the release film of the present invention will be described.

There are various methods for polymerizing PPS, but alkali sulfide, p-dihalobenzene (main monomer) and, if necessary, a small amount of subcomponent monomer are blended, and the presence of a polymerization aid in a polar solvent. A method of polymerizing at a high temperature and a high pressure below is preferable because the polymerization degree of the obtained polymer is easily increased. In particular, it is most preferable to use sodium sulfide as an alkali sulfide, p-dichlorobenzene as a main component monomer, and N-methyl-2-pyrrolidone as a solvent.

If necessary, inorganic or organic particles are added to the PPS thus obtained.

Next, as a method for obtaining an unstretched sheet,
A method of supplying the above-mentioned PPS to a melt extruder represented by an extruder, melting at 290 ° C. to 360 ° C., extruding from a slit-shaped die, casting on a rotating drum, and quenching is common. is there. Further, if necessary, heat treatment and crystallization may be performed to improve heat resistance and mechanical properties.

In order to obtain a biaxially stretched film, which is the most preferred embodiment of the present invention, a substantially amorphous unstretched sheet is formed at 85 to 105 ° C. in the machine direction and the width direction, respectively.
A method of stretching by up to 5 times and heat setting is used. As the stretching method, any method such as a sequential biaxial stretching method using a roll group and a tenter, a simultaneous biaxial stretching method using a tenter, and a tube stretching method can be applied. The sequential biaxial stretching method using a roll group and a tenter is most preferably used. After the heat treatment, if necessary, the material may be subjected to limited shrinkage (relaxation) vertically and horizontally within a range of 0 to 20% at a temperature equal to or lower than the melting point of PPS.

In the present invention, it is preferable to further perform an annealing treatment in order to keep the heat shrinkage of the release film within the above range. The annealing treatment may be performed continuously after the above-mentioned heat setting or limited shrinkage, but after at least once cooling to room temperature, treatment at 120 to 200 ° C. for 10 seconds to 30 minutes under no tension or small tension. It is. Of course, it is also possible to process after winding after heat setting or limited shrinkage.

In the present invention, the coating layer made of a silicone resin can be provided in any of the above-mentioned film forming steps. It can also be applied after winding once. As a coating method, a coating method such as a reverse coating method or a gravure coating method can be adopted, and it is preferable that the PPS film is subjected to a surface treatment such as a corona treatment or a plasma treatment before the application. If the silicone is a solution type, the silicone can be applied as a solution of several% to several tens% depending on the solvent, and if the silicone is an emulsion type, it can be applied by dispersing in water or an organic solvent. Curing is carried out by an addition reaction and a dehydrocondensation reaction with a catalyst and heat depending on the type of silicone. Generally, curing is performed at 80 to 200 ° C for 10 minutes.
It is performed by processing for seconds to several hours. Note that this curing may also serve as the annealing treatment.

[0022]

The present invention will be described below in more detail with reference to examples. The evaluation was performed as follows.

(1) Heat Shrinkage Rate A film having an initial length A was placed in a hot air oven at 100 ° C.
When the length after heating for 0 minute is B, 100 × (A
-B) / A defines the heat shrinkage (%).

(2) Surface roughness Measured according to JIS R-0601.

(3) Melt viscosity 1 mm in diameter and 10 mm in length using a heightening type flow tester
At use the mouthpiece 300 ° C. shear rate 200 sec ^-1
It measured under.

(4) Flatness of Green Sheet To 100 parts by weight of the ceramic raw material powder, 10 parts by weight of polyvinyl butyral as a binder resin and 90 parts by weight of a mixed solvent of toluene / ethyl acetate / butanol were added. A ceramic slurry was prepared using the slurry.
This slurry was applied on a carrier film (release film) using a doctor blade to a dry film thickness of 100 μm, and dried at 100 ° C. for 90 minutes to form a green sheet. The flatness of the obtained green sheet was visually determined according to the following criteria. ：: good flatness without undulation △: large undulation with a period of several cm ×: many wrinkles with undulation

(5) Peelability The state when the release film was peeled off from the green sheet obtained above was judged according to the following criteria. ○: there is no delamination of the ceramic layer △: × number of delamination parts per 1 m ² is less than 5: there is a 1 m ² per 5 or more delaminated portion

Example 1, Comparative Examples 1-2 (1) Preparation of Biaxially Oriented PPS Film 32.6 kg of sodium sulfide (25
0 mol, containing 40 wt% of water of crystallization), 100 g of sodium hydroxide, 36.1 kg (250 mol) of sodium benzoate, and N-methyl-2-pyrrolidone (hereinafter NMP)
79.2 kg), and after dehydration at 205 ° C., 37.5 kg (255 mol) of 1,4-dichlorobenzene (abbreviated as p-DCB), and 20 MPa of NMP.
0 kg was added, and the mixture was reacted at 265 ° C. for 3.5 hours. The reaction product was washed with water and dried to obtain 21.1 kg (yield 78%) of a PPS polymer composed of 100 mol% of p-phenylene sulfide unit and having a melt viscosity of 2500 poise.

To this composition, 0.9 wt% of calcium carbonate fine powder having an average particle diameter of 1 μm and 0.05 wt% of calcium stearate are added, and the mixture is melted at 310 ° C. with an extruder having a diameter of 40 mm, and a 95% cut pore diameter of 10 μm
After filtration with a film of length, length 400mm, gap 2m
extruded from a T-die with a linear lip of
Cast on a metal drum kept at 5 ° C, solidify by cooling,
An unstretched film having a thickness of 920 μm was obtained.

The film was stretched at a film temperature of 100 ° C. and a stretching speed of 2000 by a longitudinal stretching device comprising a group of rolls.
The film is longitudinally stretched 3.6 times at 0% / min, and subsequently at a temperature of 100 ° C. and a stretching speed of 1500% / min using a tenter.
It is stretched 4 times in the horizontal direction, and in the subsequent heat treatment chamber in the same tenter,
The substrate was heat-treated at 75 ° C. for 5 seconds.

Further, in a relaxation room following the heat treatment room in the same tenter, relaxation is performed by reducing the width of the tenter rail by 7% at a temperature 10 ° C. lower than that of the heat treatment for 5 seconds. (Referred to as film A).

(2) Annealing treatment The obtained PPS-BO was tensionless in the width direction and 0.5 kg in the longitudinal direction using an annealing treatment device comprising a group of rolls.
The film was annealed at 170 ° C. for 3 minutes under a tension of / cm to obtain a film (film B).

(3) Corona treatment One surface of the film B was subjected to corona treatment. Processing volume is 30
W · min / m ² .

(4) Preparation of Silicone Resin Coated Film A toluene solution containing a thermosetting silicone compound (SRX- 211 manufactured by Dow Corning Toray Silicone Co., Ltd .: 100 wt. Parts, SRX-CAT: 0.6 parts by weight, toluene: 500
(Part by weight of the solution) was applied as a solid content at a rate of 1.0 g / m ² and cured by passing through hot air at 150 ° C. for 30 seconds to produce a silicone-coated film (Film C). The surface roughness of the film C is 0.056
μm / 0.050 μm (coated surface / uncoated surface).

(5) Evaluation Table 1 shows the evaluation results of Films A, B and C. It is understood that the film C has good peelability and flatness. On the other hand, films A and B were insufficient in peelability or flatness.

Comparative Example 3 A silicone-coated film was produced in the same manner as Film C except that PPS-BO was changed to PET-BO ("Lumirror" 75 μm, manufactured by Toray Industries, Inc.) (Film D).

The obtained film had insufficient flatness as shown in Table 1.

Examples 2 and 3 and Comparative Example 4 The film C of Example 1 was used, except that the heat shrinkage of the film was changed by changing the annealing conditions such as temperature and time.
A silicone-coated film was produced in the same manner as described above (films E, F, and G).

Examples 4 and 5 A toluene solution comprising a thermosetting silicone compound was applied to a PPS-BO single-sided corona-treated product (type 3030, 75 μm, manufactured by Toray Industries, Inc.) in the same manner as in Example 1,
The mixture was passed through hot air at a temperature of 10 ° C. for 10 seconds and 60 seconds, and cured and annealed to produce silicone-coated films (Films H and I).

The evaluation results of the film are shown in Table 1, and it is understood that the silicone coated film within the range specified in the present invention has good flatness and releasability.

Example 6 A toluene solution comprising a thermosetting silicone compound was changed to the following coating solution, and the silicone compound KS- manufactured by Shin-Etsu Silicone Co., Ltd. was used.
722: 100 parts by weight Curing agent C-PL-3: 3 parts by weight n-hexane: 897 parts by weight A silicone-coated film was produced in the same manner as the film C of Example 1 except that it was dried at 80 ° C. (film) J).

As is clear from Table 1, the obtained film had good surface properties and peelability.

[0043]

[Table 1]

[0044]

The release film of the present invention is provided with a silicone resin layer on the surface to have a specific heat shrinkage,
Heat resistance, water resistance and solvent resistance are improved, and when used as a carrier sheet such as a ceramic sheet, a green sheet having good flatness and releasability can be provided.

Therefore, the release film of the present invention can be applied not only to various types of carrier sheets but also to various types of release applications such as labels, adhesive tapes and seals.

────────────────────────────────────────────────── (5) References JP-A-5-261868 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 C09J 7 / 00-7/04 H01G 4/12

Claims (1)

(57) [Claims] 1. A polyphenylene sulfide film having a coating layer made of a silicone resin on at least one surface thereof,
A release film characterized in that a heat shrinkage at 100 ° C. for 30 minutes is 0.3% or less.