JPH02154097A - Mold release paper - Google Patents

Abstract

PURPOSE:To obtain a mold release paper, consisting of a base paper, coated or impregnate with a specific filler and mold release layer, excellent in water, oil, solvent and heat resistance and capable of exhibiting excellent dimensional stability even at high temperatures and humidities. CONSTITUTION:The objective mold release paper consisting of a base paper, coated or impregnated with a filler consisting of a mixture of a PVA-based synthetic resin with a soluble zirconium compound (preferably zirconium oxychloride, sulfate or nitrate) and a mold release layer formed on the surface of the above-mentioned base paper. Furthermore, the afore-mentioned mixture is preferably prepared by mixing 100pts.wt. PVA-based synthetic resin with the soluble zirconium compound in an amount of 0.5-20pts.wt. expressed in terms of ZrO2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a release paper using a base paper coated with or impregnated with a filler to prevent penetration of a release agent.

[Background of the invention]

Release paper is obtained by applying a release agent to the surface of the base paper, but when the release agent penetrates into the base paper when applying the release agent, the amount of release agent present on the surface of the base paper increases. Therefore, in order to give the release paper good release properties, the amount of time required to apply the release agent increases, which increases the material cost of the release paper.

Therefore, when producing release paper, a release agent is applied after the base paper is sealed.

Such sealing treatment is carried out by applying a filler to the surface of the base paper, or by mixing the filler into pulp slurry during papermaking of the base paper. Such a filler not only acts to seal the base paper, but also strengthens the paper quality or enhances dimensional stability.

[Conventional technology]

Conventionally, polyvinyl alcohol has been used as this type of filler.

[Problem to be solved by the invention]

To produce release paper, as described above, a solution of a release agent in an organic solvent, especially doluol, is applied to the surface of the release paper.

Apply an aromatic organic solvent solution such as Kijiroru and dry. However, polyvinyl alcohol has poor water, oil, and solvent resistance, and polyvinyl alcohol may absorb moisture when applying a mold release agent, or swell or dissolve in the organic solvent of the mold release agent, reducing its sealing effect. Otherwise, the strength of the base paper may be reduced and deformation may occur, and there are also problems with dimensional stability at high humidity.

[Means for solving problems]

The present invention provides a release paper using a base paper coated with or impregnated with a filler made of a mixture of a polyvinyl alcohol-based synthetic resin and a soluble zirconium compound, as a means of solving the above-mentioned conventional problems. .

<Strengthening agent> The reinforcing agent of the present invention is a mixed solution of a polyvinyl alcohol-based synthetic resin and a soluble zirconium compound.

The above-mentioned polyvinyl alcohol-based synthetic resins include polyvinyl alcohol with various degrees of saponification and polymerization, or copolymers of vinyl acetate and monomers copolymerizable with vinyl acetate, such as allyl alcohol, impropenyl alcohol, and vinyl ethers. Saponified products, or modified polyvinyl alcohols obtained by modifying the above-mentioned polyvinyl alcohols with formaldehyde or the like are included.

Examples of the above-mentioned soluble zirconium compounds include compounds that are water-soluble or become water-soluble with acid, such as zirconium halides such as zirconium oxychloride, hydroxyzirconium chloride, zirconium tetrachloride, and zirconium bromide, zirconium sulfate, basic zirconium sulfate, Examples include zirconium salts of mineral acids such as zirconium nitrate, zirconium salts of organic acids such as zirconyl acetate and zirconyl formate, zirconium complex salts such as ammonium zirconium carbonate, sodium zirconium sulfate, ammonium zirconium acetate, sodium zirconium oxalate, and ammonium zirconium citrate. be done. Among these compounds, zirconium oxychloride, zirconium sulfate, and zirconia nitrate 11 are more preferred.

The polyvinyl alcohol synthetic resin and the soluble zirconium compound are preferably mixed in an amount of 0.05 to 35 parts by weight based on ZrO2 based on 100 parts by weight of the polyvinyl alcohol synthetic resin, More preferably, the soluble zirconium compound is mixed as ZrO in a ratio of 0.5 to 20 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol synthetic resin.

The above mixture is provided as a solution, and the solvent used is water or an organic solvent compatible with water such as methanol, ethanol, acetone, dioxane, etc.

The above mixture is usually provided as a solution with a concentration of 1 to 30% by weight.

<Sealing method> To treat base paper using the sealing agent of the present invention, there are a method of coating the base paper with the sealing agent, a method of immersing the base paper in the sealing agent, a method of adding the sealing agent to pulp slurry. A method of mixing the filler and making paper to obtain a base paper, a method of mixing the filler with a pulp slurry and making paper to obtain a base paper, and further applying a filler to the base paper, There is a method in which a base paper is obtained by mixing the base paper with a filler and then making paper, and then immersing the base paper in a filler. In either case, it is ultimately necessary to bring the filler into an alkaline state and cure it. In order to make the sealant alkaline, a latent alkali that decomposes to produce an alkali, such as sodium formate, potassium formate, sodium acetate, potassium acetate, ammonium acetate, ammonium formate, etc., is mixed in advance into the sealant of the present invention. A method of coating or impregnating the sealant on paper and/or mixing it with a pulp slurry, and a method of coating or impregnating the sealant on the base paper without making it alkaline and/or mixing it with the pulp slurry and adding it to the resulting base paper. There is a method of contacting with alkali. In the former case, when the treated base paper is heated and dried, it becomes alkaline and the filler hardens; in the latter case, the filler hardens when the treated base paper is brought into contact with an alkali.

<Other Ingredients> The filler of the present invention may further contain polyvinyl alcohol or polyethylene glycol.

Polypropylene glycol, ethylene glycol.

Propylene glycol, starch, modified starch, carboxymethyl cellulose, gelatin, surfactant.

Mineral oil, animal and vegetable oil, modified mineral oil, modified animal and vegetable oil.

Antibacterial and antifungal agent, fragrance + p)l regulator, rosin, polyacrylamide, acrylic resin emulsion, synthetic rubber latex, phenolic resin, urea resin.

Sizing agents such as melamine resin, urethane resin, epoxy resin, alkyl ketene dimer, alkyl kenyl or alkyl succinic anhydride, size fixing agent, antifoaming agent, pigments such as clay, kaolin, calcium carbonate, barium sulfate, titanium oxide, etc., and dyes. .

Other ingredients such as fluorescent bleaches may also be added.

<Release agent> There are known mold release agents to be applied to the base paper reinforced as described above, such as stearate, silicone, soap, and fluororesin. It is applied to the surface of the base paper as a solution dissolved in a solvent mainly composed of an aromatic organic solvent such as. The aromatic organic solvent may optionally include alcoholic organic solvents such as methanol, ethanol, impropatol, n-butanol, etc.
Other organic solvents may be added, such as acetic ester organic solvents such as ethyl acetate and PlIn-butyl acetate, and ketone organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

The above-mentioned release agent is usually applied to one side of the above-mentioned base paper, but in the case of release paper for special purposes, it may be applied to both sides. The amount of coating is usually 10 to 100 g per side of the above base paper.
The solid content should be about lrd. After applying the mold release agent, heating drying at about 50 to 80° C. is performed if desired.

[Effect]

The soluble zirconium compound, which is a component of the filler of the present invention, becomes a zirconium ion with a maximum coordination number of 8 in an aqueous solution, and forms a stable complex with the hydroxyl group contained in the polyvinyl alcohol synthetic resin. In an alkaline state, zirconium acts as a crosslinking agent for polyvinyl alcohol synthetic resin, forming a three-dimensional structure. The above-mentioned three-dimensional polyvinyl alcohol synthetic resin is extremely tough and has water resistance, oil resistance, solvent resistance, and heat resistance.

〔Effect of the invention〕

Therefore, the base paper treated with the sealing agent of the present invention has a high degree of water resistance, oil resistance, solvent resistance, and heat resistance, and it does not absorb moisture even under high humidity or is free from organic solvents when applying the mold release agent. Sealing is performed reliably without swelling or dissolving when in contact with paper, and the base paper does not lose strength or deform, and has excellent dimensions even at high temperatures and/or high humidity. This indicates stability.

Example 1 [Adjustment of filler A] Degree of polymerization: 1500. Zirconyl nitrate (ZrO(No3) 2-2H, O1 crystal) L containing 35% ZrO2 in 100g polyvinyl alcohol with a degree of saponification of 98.8 mol%
og was added and dry mixed in a mortar, water was added and dissolved by heating to prepare 1000 g of mixed solution A.

Add to the above mixed solution A 10 of the same kind of polyvinyl alcohol.
Filler A was obtained by adding 1000 g of a wt% aqueous solution and 30 g of ammonium acetate.

Example 2 [Preparation of filler B] ZrO,
, 35% by weight of zirconyl nitrate (ZrO(NOl)
Mixed solution B was prepared by adding 16 g of 22H20) and further adding water to make the total amount 1250 g.

A filler B was obtained by further adding 2 g of funnel oil to the above mixed solution B.

Example 3 [Preparation of filler C] Filler C was obtained by further adding 200 g of a 10% polyacrylamide aqueous solution to the mixed solution A of Example 1.

Example 4 [Manufacture of test paper] To a pulp slurry (L-BKP, freeness 300 ml csf) with a concentration of 2% by weight, reinforced rosin was added as a sizing agent to the pulp solid content at 0.5% heavy electric content in terms of solid content. A sulfuric acid band was added in order of 2% by weight, and water was further added to dilute the slurry solid content to 1% by weight. Next, the test paper was pressed using an automatic press machine at 8 kg/cJ for 7 minutes, and further dried using a rotary dryer at 1.20°C for 4 minutes to obtain a test paper.

Example 5 [Manufacture of base paper A] 20 g of filler A was added to one side of the test paper obtained in Example 4.
rr? Apply with a coil coater in the amount of ■20℃
Base paper A is produced by heating and drying for 5 minutes.

Example 6 [Manufacture of base paper B] The test paper obtained in Example 4 was immersed in a tank filled with sealant B to impregnate it in an amount of 30 g/rrr, and further coated with a 1% by weight sodium carbonate aqueous solution on both sides. After spraying from 130
Base paper B is produced by heating and drying at ℃ for 5 minutes.

Example 7 [Manufacture of base paper C] In Example 4, 1% by weight of filler C and 0.03% by weight of sodium formate were further added before adding reinforced rosin and polysulfuric acid band, and then the base paper was prepared in the same manner. Manufacture C.

Comparative Example 1 [Manufacture of base paper] One side of the test paper obtained in Example 4 was coated with a 10 wt% aqueous solution of polyvinyl alcohol having a degree of polymerization of 1500 and a degree of saponification of 98.9 mol% in an amount of 20 g/rd using a coil coater. The base paper is prepared by coating the base paper and drying it by heating at 120°C for 5 minutes.

Comparative Example 2 [Manufacture of base paper E] The test paper obtained in Example 4 was prepared with a degree of polymerization of 1700 and a degree of saponification of 98.
．． It was immersed in a tank filled with a filler made by adding 2 g of funnel oil to a 10 wt. Paper E is manufactured.

Comparative example 3. [Manufacture of base paper F] In Example 4, the degree of polymerization was further increased to 1500, and the degree of saponification was 98.
．． 9 mol% polyvinyl alcohol 10% by weight aqueous solution 2
000 g of polyacrylamide 10% by weight aqueous solution
00 g of the filler prepared by adding 1% by weight of the filler was added before adding the reinforced rosin and the double sulfuric acid band, and then the base paper F was prepared in the same manner.

Groups MA, B, C prepared as described above.

For D, E, and F, dimensional stability, aqueous spirit resistance, and solvent resistance were measured.

1. Dimensional stability A test piece (15 x 250 mm) of the above base paper was heated at 25°C, 60°C.
%RH (standard conditions) for 24 hours and then measure the dimensions. Next, the base paper was heated at 25°C and 80% RH (
After being left for 24 hours under conditions of 25° C. and 35% RH (low humidity), the dimensions are measured. Table 1 shows the results of calculating the dimensions when left under high humidity conditions and low humidity conditions, setting the dimensions when left under standard conditions as 100.

After being immersed in water for 1 hour, a tear test was conducted using a Tensilon tester under the conditions of a span of 1801TI11, a load of 20 cm, and a tensile rate of 30 cm/min, and the wet tear length was determined according to a conventional method. For comparison, a similar test piece was heated at 25℃ and 60%
After leaving it at RH for 24 hours, the standard tearing length was determined in the same manner. The results are shown in Table 2.

Base paper A using the filler of the present invention as shown in Table 1
, B, and C have smaller dimensional changes under high-humidity and low-humidity conditions than base papers E and F that use a conventional filler (polyvinyl alcohol).

2. Deionized a test piece (15 x 250 mm) of the above base paper based on liquefied water.As shown in Table 2, base paper A was prepared using the filler of the present invention.
, B, and C exhibit larger values for both standard tear length and wet tear length than base papers E and F, which use a conventional reinforcing agent (polyvinyl alcohol).

3. Solvent resistance After immersing a test piece (15 x 250 nyn) of the above base paper in Kijiroll for 1 hour, 2. The oil immersion fracture length was determined in the same manner as the water resistance. Standard tear length is 2. The results obtained for water resistance are used. The results are shown in Table 3.

After coating, dry at 60° C. for 10 minutes. About the release paper test piece obtained in this way 2
．． The breaking length was determined in the same manner as the water resistance.

Standard tear length is 2. The results obtained for water resistance are used. The results are shown in Table 4.

As shown in Table 3, base paper A using the filler of the present invention
, B, and C exhibit larger values of the kijiroll immersion tearing length than base papers E and F, which use a conventional reinforcing agent (polyvinyl alcohol).

Further, the dimensions of the release paper test piece before and after application of the release agent were determined, and the dimensions before application of the release agent were set as 100, and the dimensions after application of the release agent were calculated. Table 5 shows the results.

Below, 7F, Song 4, Release agent application test: 50g of 50% by weight silicone doluol solution was applied to one side of the above base paper test piece (15X25011I11)/Additionally, acrylic adhesive was applied to the coated side of the above release paper test piece. A cycle of pressing the coated polyester film with a force of 500 g/ci and then peeling it off is repeated, and the number of times until the adhesive is transferred to the coated surface of the release paper test piece is measured. The results are shown in Table 6.

Table 6

Claims (1)

[Claims] A release paper consisting of a base paper coated with or impregnated with a filler made of a mixture of a polyvinyl alcohol-based synthetic resin and a soluble zirconium compound, and a release layer formed on the surface of the base paper.