DE2513863A1 - PROCESS FOR THE MANUFACTURING OF HEAT-REGENERABLE, IN PARTICULAR HEAT-SHRINKABLE MOLDED PARTS FROM THERMOPLASTIC MATERIAL - Google Patents

Description

B4TENMNH0LTE ^ö BROSE ^DKa BROSE

D-8023 Munich-Pullach, Wiener Str. 2; Tel. (089) 7 93 30 71: Telex 5212147 brosd; Cables: -.Patentibus »Munich

Graduate engineer

Your mark: Day: 27th March 1975

Yourref .: Date: DBr / Pz - Case 3291

COAL INDUSTRY (PATENTS) LIMITED, Hobart House, Grosvenor Place, London SWlX 7AE, England

Process for the production of molded parts which can be regenerated under heat, in particular heat-shrinkable thermoplastic material.

The invention relates to a method for producing heat-regenerable, in particular heat-shrinkable Molded parts made of thermoplastic material, with the invention in particular with heat-shrinkable products which are made from plasticized polyvinyl chloride materials.

In recent years, the use of heat shrinkable Products have grown significantly in many fields including packaging, engineering, electronic and electrical industry. The property of certain plastic materials to shrink when they exposure to heat enables a product to fit snugly around an object to be protected. On the

509840/0843

in the electrical field, for example, heat-shrinkable sleeves manufactured, which can be pushed over an electrical connection and then heat-shrunk over this connection to form an electrically insulating coating, which at the same time has a corrosive effect on the entry Environmental influences prevented. For example, in the case of seafaring, the stocking of rope ends with taklingen, which heretofore has been a time consuming occupation, accelerated by placing a heat shrinkable plastic tube over the end of the rope is pushed and the tube is heated so that it shrinks in the direction of the rope.

The heat shrinkable electrical insulators mentioned above may be made by any known molding method such as injection molding, compression molding, dip molding, etc. will. The moldings are then heated to around 130 to 200 ° C and in the warm state diametrically by means of a cool rod of circular cross-section, which is usually coated with PTFE is widened to the corresponding size, which corresponds, for example, to twice the diameter of the original molding. The molding is cooled to ambient temperature while it is on the expansion rod. He will subsequently is taken down and gives a heat-shrinkable product.

In order to produce a dip casting, a molded part is usually made made of aluminum or an aluminum alloy, with a temperature of about 130 to 250 ° C in a PVC Plastisol or paste is dipped and after a predetermined time is pulled out with a coating of the required thickness. The coating is then completely gelled or cured by heating it to about 130-250 ° C. The for Heating required heating margin can easily be determined through experimentation. After heating, the coating or The molding is peeled from the molding at the required temperature and expanded using a cool PTFE rod

509840/0843

and then cooled and gives the desired heat shrinkage bare molding.

Heat-shrinkable polyvinyl chloride molded parts of a Shore A hardness of 95 or more made in this way are satisfactory, but for products with a Shore A hardness less than 95 unsatisfactory because it shrink significantly during storage at room temperature.

The invention is therefore based on the object of an improved method for producing heat-regenerable, in particular heat-shrinkable molded parts made of thermoplastic To create material, in particular polyvinyl chloride, which can have a Shore hardness above or below 95 and which is at room temperature can be stored for significant periods of time without significant regeneration or recovery or Show shrinkage.

The present invention provides a method of manufacturing of moldings made of thermoplastic material which can be regenerated or recovered under heat, in particular heat-shrinkable created in which a heat recoverable thermoplastic Material is shaped into a desired shaped body, then the shaped body at a temperature between 130 to 200 ° C diametrically is expanded or contracted, using a hot rod to expand or contract, or multiple rods and in which the shaped body, which has changed in its dimensions, is then rapidly cooled while it continues is on the rod or rods.

The rod or rods are preferably at a temperature between the limits of 90 to 130 ° C during expansion held and the rapid cooling can be achieved that the shaped body on the rod or rods in water at room temperature is immersed.

509840/0843

The rod (s) is (are) preferably made of PTFE.

The original molded body is preferably made by dip molding, although the present invention applies equally Articles made by injection molding, compression molding, extrusion or other molding processes are applicable.

The shaped body is preferably subjected to a diametrical expansion in order to obtain a heat-shrinkable product.

The plastic material is preferably a plasticized polyvinyl chloride.

The invention is explained in more detail below with the aid of an example.

example

In an application example of the present invention, a molded part made of aluminum in the form of an electrical Connection heated to 235 ° C and then immersed in a polyvinyl chloride plastisol for 10 seconds. The molding was then pulled out of the plastisol and the deposited coating, which remained on the molding, to a temperature heated to about 180 ° C in order to completely gel or cure the polyvinyl chloride. The molded body obtained, the one Shore A hardness of 90 at room temperature, was then removed from the molded part, heated to 1 ^ 0 ° C and on the double its original diameter by means of a PTFE rod at a temperature of 100 ° C. During the Molded body was held in its expanded shape on the rod, it was immersed in a water bath at room temperature. The expanded molded body was removed after cooling to room temperature and retained its expanded dimensions.

509840/0843

The molded article was at room temperature for a significant period of time stored without showing any substantial recovery or shrinkage. The molding was over for use an electrical connection pushed and heated to about 120 ° C by means of a V / arm air flow. This led him to the Connection shrank and formed a tight fit on this.

All of the technical details mentioned in the description are important for the invention.

509840/0843

Claims (7)

PATENT CLAIMS , 1 · / Process for the production of heat-regenerable or recoverable, in particular heat-shrinkable moldings thermoplastic material, in which a molded body made of thermoplastic material heats and expands or contracts is, characterized in that the molded body consisting of the thermoplastic material at a temperature between 130 to 200 ° C on a heated expansion or contraction bar is expanded or contracted and that the shaped body located on the rod is then rapidly cooled. 2. The method according to claim 1, characterized in that the rod is heated ^{to a temperature between 90 and 130 0 C.} 3. The method according to claim 1 or 2, characterized in that the molded body consisting of the thermoplastic is produced by dip molding at a temperature of ⁰ to 250 ° C. 4. The method according to any one of the preceding claims, characterized in, that the molded body consisting of the plastic consists of plasticized polyvinyl chloride. 5. The method according to one or more of the preceding claims, characterized in that the plastic material from which the molding is produced has a Shore A hardness of less than 95. 6. The method according to one or more of the preceding claims, characterized in that the rapid cooling by immersion is carried out in water at room temperature. 7. Plastic product that can be regenerated or recovered under heat, produced according to one or more of the preceding claims. 509840/0843