CS216155B2

CS216155B2 - Method of making the relief design by selective expansion of the thermoplastic polymerous substance

Info

Publication number: CS216155B2
Application number: CS851071A
Authority: CS
Inventors: Peter W Jones
Original assignee: Congoleum Corp
Priority date: 1971-12-07
Filing date: 1971-12-07
Publication date: 1982-10-29

Description

The invention relates to a method of forming a relief pattern by selectively expanding a thermoplastic polymeric substance.

British Patent Specification No. 1 147 983 discloses a method of forming a relief pattern by selective expansion of a thermoplastic polymeric material by treating the expandable composition comprising the thermoplastic polymeric mass and the blowing agent into a sheet formation on selected surface areas of the sheet. The activating liquid containing the blowing agent activator is applied and the sheet is heated, whereby it spreads on the surfaces of the sheet in contact with the agent containing the blowing agent to a greater extent than on the other surfaces and thus expands the sheet differently.

A disadvantage of this known process is that the surface of the sheet is, after the embossing pattern has been formed, doubles, both in the areas exposed to the activating liquid and in the areas where the activating liquid has not acted, and the drawing of the pattern does not have perfect sharpness.

These drawbacks are overcome by the invention, wherein the expandable composition of the above type further comprises at least one tin compound present in an amount of from 0.2 to 5% by weight. parts per 100 wt. parts of the polymeric substance.

The tin compound according to the invention may be, for example, dialkyl tin maleate, dialkyl tin phthalate, tin thio compound, tin mercaptil or dibutyl tin maleate.

The embossed surface formations produced by the method of the invention have a smooth and apparent surface, both in areas exposed to the activating liquid and in areas not exposed to the activating liquid, compared to products made according to British Patent Specification No. 1,149,983. The drawing of the embossed pattern is clear and the cell structure is regular. In addition, the tin compounds have lower toxicity than the commonly used barium or cadmium stabilizers and, where toxicity is an important factor, the process of the invention is more advantageous from this perspective as well.

The method according to the invention has particular application in the production of flooring and wall and ceiling cladding materials. Of course, materials resistant to mechanical stress are required for flooring. The flooring typically consists of a textile backing laminated to a main plastic backing plate, which may be expanded or unexpanded, and onto which a surface board that is differently expandable to form a decorative wear layer is laminated.

21B1S5

The thermoplastic polymer mass of the expandable composition may be a polycondensate such as a polyamide (e.g. polycaprolactam or polyaminoundecanoic acid or a polyester (e.g. tertiarylate polyesters). The thermoplastic polymer may also be an addition polymer such as polyolefin (e.g. polyethylene or polypropylene), polyacrylate (e.g. polymethylmethacrylate) , polystyrene or a halogen-substituted olefin polymer such as polyvinyl chloride Besides polyvinyl chloride, for example, vinyl chloride copolymers with vinyl fatty acid esters such as wool acetate, or other polymerizable vinyl group monomers (such as vinylidene chloride, acrylic acid) may be used in addition to polyvinyl chloride and styrene].

The blowing agent can be any blowing agent whose decomposition temperature is lowered in the presence of various compounds known as activators. However, it is essential that the blowing agent is suitable for the polymer used, that is, the blowing agent must decompose at a temperature at which the polymer or the mixture containing it can expand. Examples of blowing agents are azodicarbonamide, barium azodicarboxylate, benzenesulfonylhydrazide (pp- ¹ -oxybis) and benzenesulfonylsemicarbazide (ppb-oxybis), preferably azodicarbonamide.

In particular, the preferred composition of the expandable composition is a combination wherein the polymeric material is derived from vinyl chloride and the blowing agent is azodicarbonamide. The particle size of the azodicarbonamide has a great effect on achieving the optimum degree of differential expansion between the activated and non-activated sites of the expandable composition. Most preferably, the azodicarbonamide has a specific surface area of the order of 4000 to 6000 cm ² / g, the particle size being between 3 and 15 microns. The amount of azodicarbonamide is preferably 1 to 10 wt. %, Based on the weight of the polymer formed from the components derived from vinyl chloride.

Various tin compounds may be used according to the invention, but those usually used as stabilizers for polymeric substances are particularly preferred. Examples of suitable tin compounds are dialkyl tin maleate, for example di-low alkyl tin maleate, such as dibutyl tin maleate, dialkyl tin laurate, for example di-low alkyl tin laurate, tin thio compound, tin mercaptide and the like;

The expandable composition may also contain other ingredients suitable for obtaining the desired product. These additional ingredients are plasticizers, solvents, diluents, fillers, colorants, hardeners and other stabilizers.

The blowing agent activator used in the composition containing the activator may be any of the compounds which lower the decomposition temperature of the blowing agent. These compounds are zinc compounds (such as zinc oxide, zinc caprylate, zinc nitrate and zinc fatty acid soaps), cadmium compounds (such as cadmium caprylate, cadmium capropane, cadmium laurate, cadmium myristate and cadmium fatty acid soaps), lead compounds (such as , lead phthalate, lead phosphite and lead aran], urea, borax, ethanolamine, glycols and other chemically active blowing agents such as benzenesulfonhydrazine, but preferably the activator is a zinc compound such as zinc caprylate or zinc nitrate.

The activating liquid containing the blowing agent activator is essentially a mixture of the activator solution or dispersion and the solution or dispersion of the film-forming component or binder resin and the dye or pigment. The dispersion medium for the activator is preferably an ester such as ethyl acetate. Suitable film-forming components or binder resins are polyvinyl chloride or a copolymer of vinyl chloride and vinyl acetate, acrylic resins, polyurethanes, cellulose acetate, polyesters, polystyrenes, elastomeric materials, epoxy resins, silicones and other polymers. The solvents or dispersion medium for the film-forming component or binder are preferably substances used as the dispersion medium for the vinyl chloride-derived polymer or copolymer used in the expandable composition, as this improves the penetration of the activator from the activating composition into the expanded sheet. Suitable solvents are ketones such as tetrahydrofuran, cyclohexanone, methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate, chlorinated hydrocarbons such as ethylene dichloride and methylene chloride, and nitro compounds such as nitrobenzene and nitropropane. Diluents can be used to inhibit the volatility of the solvent in the composition containing the activator, which is undesirable in printing application. Suitable diluents are hydrocarbons such as toluene and xylene.

The activating liquid should contain 2 to 25 wt. % of the activator and preferably comprises 5 to 20 wt. % activator. The consistency of the activating fluid has a significant effect on achieving optimum results. The solids content of the activating liquid is preferably 5 to 30 wt. %.

The expandable composition is preferably in the form of plastisol. Suitable plasticizers in the manufacture of plastisol are phthalic acid esters (such as butylbenzyl phthalate, dioctyl phthalate, dialphanyl phthalate and diisoctyl phthalate), adipic acid esters (such as dioctyladipane), sebacic acid esters (such as dloctylsebacanes), and phosphoric acid phosphate esters (such as trisphosphate).

The amount of plasticizers and fillers present in the expandable composition can vary within wide limits. For example, the plasticizers may be present in an amount of 40 to 100% by weight. parts per 100 wt. parts of the polymer. Preferably, the amount of plasticizer is in the range of 50 to 80 wt. parts per 100 wt. parts of the polymer.

The filler may be present, for example, in an amount of 1 to 50 wt. parts per 100 wt. resin parts. Larger amounts of filler are preferred since they allow for easier penetration of the activating liquid into the mixture.

Other suitable stabilizers may be present in the plastisol to reduce polymer degradation by heat and light. The total concentration of other stabilizers and tin compound in plastisol is usually 0.5 to 10% by weight. parts per 100 wt. parts of the polymer.

Plastisol may also contain dyes or pigments, diluents such as hydrocarbons, for example toluene, fillers and the like.

The amount of blowing agent in plastisol varies according to the desired degree of expansion. Preferably, 1 to 20 wt. parts of blowing agent for every 100 wt. parts of the polymer. Preferably, the proportion is in the range of 2 to 10 wt. parts of a blowing agent, i.e. azodicarbonamide, for each 100 wt. parts of the polymer.

The expandable composition may be formed into sheets by extrusion, casting, calendering or spreading. Preferably, the expandable composition is applied as a plastisol to a suitable surface, which may be a permanent substrate or a removed substrate, and the plastisol is gelatinized, i.e., heated for a time sufficient to bring the plastisol layer to a solid, non-tacky, solid state wherein heating is not sufficient to decompose the blowing agent.

The degree of gelatinization of the expandable composition at the time of application of the activator composition has a considerable effect on obtaining the desired effect. In order to be able to apply the composition with the activator to the surface of the sheet by conventional means, its physical state must be such that it does not adhere to the rollers of the printing device. If the sheet of expandable composition is gelatinised to a high degree, the desired effect is not achieved. For optimum results, the sheet of gelatin of the expandable composition should be gelatinized to a minimum to allow printing. Preferably, the sheet is gelatinized at a temperature in the range of 100 to 150 ° C for 2.5 to 0.5 minutes. The higher the temperature, the shorter the gelation time.

The backing may be made of a resin, fabric, impregnated filament or release agent, such as a paper coated with a fabric based on a silicone resin, alginate or casein.

The activating liquid is preferably applied to the gelatinised plastisol by any conventional printing technique. It is advisable to leave the gelatinised plastisol with a printed pattern at rest for, for example, 1 to 24 hours before any further work processes. The exact length of this time depends on the desired degree of different expansion. The degree of difference in expansion increases with the length of this time.

The embossed surface can be provided with a wear-reducing coating if desired. This can be achieved by applying to the gelatinised plastisol a layer of thermoplastic polymer material which preferably does not contain a blowing agent.

The printed and gelatinised plastisol can be heated in various ways, for example in hot air furnaces or in infrared heaters. The temperature to which the printed and gelatinised plastisol is heated is higher than the decomposition temperature of the activated blowing agent and preferably is in the range of 150 to 210 ° C. The time for which the printed and gelatinised plastisol is heated depends on the temperature and the desired degree of decomposition of the blowing agent and is preferably in the range of 15 to 300 seconds.

The invention is explained in more detail in the following two examples, in which all values given in parts refer to values given in parts by weight.

Example 1

Polyvinyl plastisol, containing:

polyvinyl chloride [Geon 121 j 100 ALIGN! parts dioctyl phthalate 65 parts dioctyladipate 10 parts epoxy soybean oil 5 parts azodicarbonamide (Genitron AG.3) 3 parts filler 35 parts dibutyltin maleate (Advastab OM.18J 1.5 part is applied in the usual manner on fabric

or - release paper to form a 0.4 mm thick layer. The layer was gelatinized at 140 ° C for 15 seconds.

The gelatinised layer is printed using a conventional rotary gravure printing device with an activating liquid comprising:

216153 acrylic polymer

Plexigum M.334 2 parts acrylic polymer

Plexigum M.345 2 parts toluene 1.3 parts methyl ethyl ketone 10.875 parts methyl isobutyl ketone 12.5 parts micronized inorganic pigment 4 parts zinc caprylate Idodated as 3.575 parts ethyl acetate (activation concentrate 3.575 parts)

The printed layer is then covered with a layer

0,1 mm thick, containing: polyvinyl chloride (Geon 121) 100 ALIGN! parts dioctyl phthalate 45 parts dioctyladipate 10 parts barium and cadmium stabilizer 1.5 part a viscosity reducing agent (Deplastcl) 1.5 part

The mass is then heated at 200 ° C for 2 minutes. After unfastening, the product is measured and a thickness of 0.79 mm on non-permeable surfaces and 1.88 mm on printed surfaces is determined. The layer thickness difference is thus 1.09 m.

Example 2

An expandable composition in the form of a polyvinyl plastisol, comprising:

type A type B type C polyvinyl chloride

(Breon P 130/1 j 100 ALIGN! parts 100 parts 100 ALIGN! parts dioctyl phthalate 65 parts 65 parts 65 parts azodicarbonamide (Genitron AC4) 3 parts 3 parts 3 parts stabilizer content · barium or barium and cadmium Mark TT - 2 parts 1.5 part dibutyltinmaleinan 1.5 part - - filler · (Calibrite) 30 parts 30 parts 30 parts titanium dioxide 5 parts 5 parts 5 parts reducing agent viscosity (NercosolJ 1 part 1 part 1 part

The expansion mixture is applied to the substrate in an amount of 150 g / m ² to form a 0.11 mm thick layer. The layer is gelatinized at 135 ° C for 60 s, cooled and printed with a liquid containing:

Activating liquid 57

Activating Fluid 58 a mixture of acrylic copolymer and vinyl chloride-vinyl acetate copolymer in ketone solvents (Medium

10/73] 66 parts 06 / parts pigment 14 parts 14 parts filler (Calofort S) 11 parts 11 parts activator (caprylan) zinc j 23.5 part 14.5 part cellosolvacetate 5 parts 5 parts methylisobutylketone 74.5 part 80.5 part

Activating fluid 57 contains 12% activator and activating fluid 58 7-5. % activator.

Solvents were evaporated from the liquid by heating at 110 ° C for 60 seconds and allowed to stand for 24 hours. Expansion is performed by heating at 200 ° C for 59 seconds for one sample group and 90 seconds for the other.

The depths of the embossed patterns, i.e. the differences in thickness in the areas exposed to the activating liquid and in the areas not exposed to the liquid, expressed in millimeters, are compiled in the following Tables I to IV. In all cases, it is apparent that the depth of the embossed pattern when using dibutyltin maleate is greater than when using barium and cadmium stabilizers.

Examination of the samples shows, both visually and to the touch, that samples 1, 4, 7 and 10, all of which have been produced by the method of the invention, have a smooth and appealing surface, both in printed and non-permeable areas. The relief pattern drawing is clear and the cell structure of all four samples is regular.

A similar examination of the remaining specimens, all made by the method of British Patent No. 1147,983, shows that their surface is pitted in both printed and impermeable areas, the pattern drawing is less sharp and the cellular structure of all eight specimens is irregular.

Table I: Activating liquid 58 (7.5% activator) heating time 59 seconds

DBCM = dibutyltin maleate

Mark TT = barium and cadmium stabilizer

sample expansible mixture type stabilizer thickness after expansion depth of embossed pattern printed area unpaved area 1 AND DBCM 0.44 0.19 0.25 2 C Mark TT 0.51 0.34 0.17 3 (B) Mark TT 0.51 0.36 0.15

Table II Activation Fluid 58 (7.5% Activator) Heating Time 90 seconds

sample expansible mixture type stabilizer thickness after expansion depth of embossed pattern printed area unprinted area 4 AND DBCM 0.49 0.175 0, 315 5 C Mark TT 0.56 0.36 0.2 8 (B) Mark TT 0.58 0.38 0.2

Table III Activation Fluid 57 (12% Activator) Warm-up Time 59 seconds

sample expansible mixture type stabilizer thickness after expansion depth of embossed pattern printed area unprinted area 7 AND DBCM 0.49 0.175 0.315 8 C Mark TT 0.54 0.315 0.225 Θ (B) Mark TT 0.54 0.35 0.19

Table IV Activation Fluid 57 (12% Activator) Warm-up time 90 seconds

sample expandable mixture

Claims

A method of forming a relief pattern by selectively expanding a thermoplastic polymeric material, wherein the expandable composition comprising the thermoplastic material and the blowing agent is treated into a sheet, the activating liquid containing the blowing agent containing is applied to selected surface areas of the sheet and the sheet is heated. wherein on the surfaces of the sheet in contact with the activator-containing substance, the blowing agent extends to a greater extent than on the other surfaces, and the sheet thus expands differently, characterized in that the expandable composition further comprises at least one

INVENTION tin compound present in an amount of from 0.2 to 5 wt. parts per 100 wt. parts of the polymeric substance.

2. The method of claim 1, wherein the tin compound is a dialkyl tin maleate.

3. The process of claim 1 wherein the tin compound is dialkyl tin phthalate.

4. The method of claim 1, wherein the tin compound is a tin compound.

5. The method of claim 1, wherein the tin compound is tin mercaptide.

6. The process of claim 1 wherein the tin compound is dibutyltin maleate.