DE2249789B2 - - Google Patents

Description

a paper bas ^ sheet -nod emen rojV ^ _has methyl cEUulose containing ^ _{a spu}

^ ^l ^ J ^^ of poly (vinyl

alcohol). _Ab i _öse papier offers an excellent

S _3s

widespread interest. S «^« ^ 35

Partitions and doors. "_

Traditionally, these laminates are successfully used.

keep by making one from a plastic layer and manure is not less on the application

a desired carrier existing sandwich shape pressures limited.

into a press and using "heat and pressure". The release coating composition of the invention is applied forms. The plastic layer can be applied as prepreg the form a carrier which is manufactured so that a resin-impregnated or resin-coated pa- 45 the coating does not penetrate excessively into the support, Adopt piers or in the form of a self-supporting A preferred carrier is one with one or more Plastic film. The carrier can consist of several intermediate coats of a conventional pigment fiber layer, a particle or a wood chip adhesive type provided paper base, which to this plate. Wean the layer materials in which the release coating is used to penetrate into the pa press are set, a piece of release paper will prevent the pier reason and the necessary for the release or another material with a release surface to ensure agile strength. Contact with the plastic layer on which the carrier according to the invention becomes when the release liner applied on the opposite side. It prevents from a negligible amount up to approximately the adherence of the plastic layer to the press and 20% methyl cellulose, based on the weight of the issued in particular to the plastic surface to be molded 55 poly (vinyl alcohol), when pressing the layer Surface properties of the release coating. As fabrics, the resins, such as polyester and acrylic materials using them in contact with the pulled-up release surface, provided excellent releasability, is molded, the plastic surface can be smooth, struc- For the poly (vinyl alcohol) components are the tured, matt, glossy or of other desired low molecular weight polyvinyl alcohols) with a special texture be. "Preferred because of the conditions in the 60. Surprisingly, a satisfied press will be and the nature of the plastic material does not have to achieve the cosmetic release if any of the Me release paper have very good release properties. thylcellulose closely related compound, such as Hy-previous Removal coatings were used for conventional vinyl ethyl cellulose or carboxymethyl hydroxy applications conventional release agents, such as silicone resins, ethyl cellulose is used in place of methyl cellulose or a chromium chloride-stearic acid complex, 65. Another indication of the unexpected results of both rather expensive release agents, polyvinyl alcohol), niche of the present invention is that, though one commonly used for casting plastic sheeting (both polyvinyl alcohol) and methyl cellulose detes release agent which, compared to the above, has long been recognized for its independent use as

Release coatings are known in the casting of vinyl films (see U.S. Pat. No. 2,819,181) when methylcellulose with polyvinyl alcohol) is combined as a release surface on cast paper, the functional quality is reduced compared to either poly (vinyl alcohol) or methyl cellulose release coatings, the can be used on cast paper alone.

Example I.

The following release coating was made by mixing the following ingredients:

Parts Solid Weight
share 100
5 Polyvinyl alcohol), aqueous solution
with 15% solids
Methyl cellulose, aqueous solution
with 5% solids
water 667
100
138

This coating was applied to a body of material ^{weighing 88 g / m 2} which had previously been coated with two separate intermediate coats of a conventional pigment adhesive composition. The release liner was drawn down with an air brush in an amount of 4.45 g / m ^{2 on a} dry weight basis and dried with air heated to 140.6 ° C.

A sandwich shape was produced by placing a polyester resin "prepreg" over a 1.27 cm thick chipboard as a carrier and then placing the coated release paper with its release surface in contact with the polyester resin layer. This sandwich mold was placed in a press and ^{pressed for 15 minutes at 21 kg / cm 2} and a temperature of 172.8 ° C., after which it was removed and cooled for 3 minutes. The release paper was then peeled off the polyester surface. It peeled off cleanly and transferred its own surface properties to the polyester surface.

Example Π

A release coating was made by mixing the following Components manufactured:

Dear Solid Weight
share 100
² Polyvinyl alcohol), aqueous solution
with 15% solids
Methyl cellulose, aqueous solution
with 2% solids
water 667
100
138

This coating composition was drawn down onto the coated base material body used in Example I with an air brush. The coating weight was 4.45 g / ^m2 .

ao A composite mold was made by placing the coated release paper over two layers of polyester-saturated kraft sheets. This Verbündform was then placed at room temperature and a pressure of 52.5 kgf / cm ² at a raised to 148.9 ⁰ C temperature. These conditions were maintained for 4 minutes and then the temperature was lowered to 22.2 ° C. The press was opened and the sheet form removed. The release paper peeled off cleanly as in Example I, and gave results that were comparable to Example I.

B e i s ρ i e 1 III

A sandwich shape was produced by laying a layer of modified acrylic resin with a thickness of 3.175 mm over a sheet of asbestos impregnated with vinyl resin. A coated release paper produced according to Example I was placed over this layer. This sandwich mold was then placed in a press and ^{pressed at 42 kg / cm 2 for} 2 minutes at 165.6 ° C., after which it was removed and the release paper peeled off from the acrylic layer. The results were comparable to those in Example I.

Claims (1)

is, provides for layering- ltbBtlera ^d > ^ ° '^ Ä alcohol) siÄg - sst 20%, based on the weight of the roiy ν _aUein ^ ₅ by the fact that the ^ j ^ Ä ,,,, ™, ÄrÄ ^ ÄS h ^vo °