WO2004012926A1

WO2004012926A1 - Hollow cylindrical moulded body based on thermoplastic polyurethane

Info

Publication number: WO2004012926A1
Application number: PCT/EP2003/007685
Authority: WO
Inventors: Johann Diedrich Brand; Herbert MÖLLERING; Daniela Herkenhoff
Original assignee: Basf Aktiengesellschaft
Priority date: 2002-07-25
Filing date: 2003-07-16
Publication date: 2004-02-12
Also published as: DE10234006A1; EP1549482A1; AU2003254361A1

Abstract

The invention relates to hollow cylindrical moulded bodies based on thermoplastic polyurethane in a temporary form, the wall of the hollow cylindrical moulded body in the permanent form having a thickness that is at least 10 % larger than the thickness of the wall of the hollow cylindrical moulded body in the temporary form.

Description

Hollow cylindrical molded body based on thermoplastic polyurethane

description

The invention relates to hollow cylindrical shaped bodies, hereinafter also referred to as "shaped bodies", based on thermoplastic polyurethane in a temporary shape, the wall of the hollow cylindrical shaped body having a thickness in the permanent shape which is at least 10% greater than the thickness of the wall of the hollow cylindrical shaped body in the temporary shape. The invention further relates to methods for fastening or sealing materials, whereby a material, e.g. a pipe, an electrical line, a nail, a screw placed in the cavity of the shaped body according to the invention, for example introducing or pushing the hollow cylindrical shaped body over the material, and then the shaped body according to the invention by heating to a temperature in the range greater than or equal to the melting temperature of the Soft phase and low melting temperature of the hard phase are converted from the temporary form into the permanent form.

Elastic plastics are often used to fasten or seal objects. A disadvantage of known solutions is, in particular, the difficult, precisely fitting insertion of the sealing or fastening material in or around the material to be fastened or sealed.

The object of the present invention was to develop a sealing and fastening material as well as a method for sealing and fastening, with which simple handling with good fastening and sealing properties is made possible at the same time. The material should have excellent mechanical properties such as low abrasion and high tear resistance.

This task could be solved by the shaped bodies shown at the beginning. Thermoplastic polyurethane, hereinafter also referred to as TPU, is used as the material for the production of the shaped bodies, which is generally known, widely described and commercially available. It is essential to the invention that the shaped body can be transferred from a temporary state in which the shaped body is in an extended state with a small wall thickness to a permanent state with a greater wall thickness of the cylinder, in particular by heating the shaped body to a temperature greater than or equal to the switching temperature and low melting temperature of the hard phase. The invention relates to the shaped body in the temporary shape, ie the elongated shape. The temporary shape is defined by the possibility of being able to be converted into the permanent shape by heating the molded body to a temperature greater than or equal to the switching temperature. The “permanent shape” of the shaped body according to the invention is, in particular, the shape of the shaped body which is present at a temperature in the range of greater than or equal to the switching temperature, ie in particular the melting temperature of the soft phase and the low melting temperature of the hard phase. The "temporary shape" of the shaped body according to the invention is, in particular, the shape of the shaped body which is below the switching temperature, ie the melting temperature of the soft phase, and by heating the shaped body to a temperature in the range of greater than or equal to the melting temperature of the soft phase and a low melting temperature of the hard phase the temporary form can be converted into the permanent form.

The transition from a temporary form to a permanent form by heating the TPU is described in the article "Shape memory polymers" by A. Landlein and S. Kelch, Angewandte Chemie, 2002. 114, 2138-2162, WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, in which terms such as "temporary shape", "permanent shape", "switching temperature" or "Ttrans" and "Tper" are also explained. The switching temperature is defined in particular as the melting temperature of the soft phase of the polyurethane, which can be determined using generally known methods. The melting temperature of the soft phase of the polyurethane is, in particular, the temperature at which the maximum of the melting peak of the soft phase is present in the DSC (differential scanning calorimetry) measurement. Tperm is in particular the melting temperature of the hard phase of the TPU, i.e. the melting temperature of the entire TPU. This melting temperature can also be determined using generally known methods, for example based on the temperature at which the melting peak of the hard phase in the DSC

(Differential Scanning Calometry) measurement is available. The switching temperature is preferably in a range from 25 ° C. to 50 ° C., preferably 35 ° C. to 50 ° C. This switching temperature can in particular be selected by selecting suitable polyols (b), which will be presented later, in particular the butane-1,4-diol and / or

Hexane-1, 6-diol adipates with a molecular weight of 2000 g / mol to 4000 g / mol, can be set specifically because of the ratio of butane-1,4-diol to hexane-1,6-diol in the polyester the crystallinity can be specifically controlled while the molecular weight remains the same. The TPUs preferably have an at least partially crystalline soft phase, since the crystallinity of the soft phase determines the "width" of the switching temperature. The shaped bodies according to the invention can be produced in the temporary shape, for example, by cold-stretching or rolling a generally cylindrical hollow TPU shaped body obtainable by known processes, for example injection molding or extrusion, starting from the permanent shape, and in the stretched shape at one Temperature remains lower than the switching temperature until the molded body has taken on this temporary shape. This form conversion from the permanent form to the temporary form takes place through the partial crystallization of the soft phase at temperatures lower than the melting temperature of the soft phase. Alternatively, it is possible, starting from the (usually present) permanent shape, to stretch the molded body at a temperature greater than or equal to the switching temperature and less than the melting temperature of the hard phase (Tperm) and to cool it down to a temperature lower than the switching temperature. By cooling to a temperature lower than the switching temperature, the molded body is fixed in the elongated, temporary shape, which only changes back to the permanent shape when heated above or equal to the switching temperature. Generally known machines or devices for stretching or rolling the shaped body can be used, for example known gusset machines or rollers. Manual stretching is also possible. The stretching can be one-dimensional or two-dimensional, that is to say in the diameter of the cylinder and / or length of the cylinder. The molded body is preferably stretched from the permanent shape to produce the temporary shape by 10% to 300%, particularly preferably by 10% to 100%, in particular 50% to 100%. The process for producing the shaped bodies according to the invention can thus preferably be carried out in such a way that the shaped body, based on the permanent shape, the wall thickness of which is at least 10% greater than the thickness of the wall in the temporary shape, by stretching or rolling at a temperature in the range higher or equal melting temperature of the soft phase and lower melting temperature of the hard phase in the temporary form and in this temporary form cools to a temperature lower than the melting temperature of the soft phase. Alternatively, it is preferably possible to produce the shaped body according to the invention in such a way that the shaped body, based on the permanent shape, the wall thickness of which is at least 10% greater than the thickness of the wall in the temporary shape, is stretched or rolled at a temperature in the range smaller The melting temperature of the soft phase is converted into the temporary shape and fixed in this stretched shape until the molded body has assumed the temporary shape with the smaller wall thickness. The shaped body in the temporary, ie elongated form, usually has a wall thickness of 1 mm to 100 mm, preferably 2 mm to 50 mm, in particular 5 mm to 30 mm. The thickness of the wall of the hollow cylindrical shaped body in the permanent shape is at least 10%, preferably 15% to 500%, particularly preferably 20% to 100% greater than the wall thickness of the shaped body in the temporary shape.

The fastening and / or sealing of materials according to the invention shown at the outset takes place by thickening the wall of the cylindrical shaped body during the transition from the elongated, temporary shape by increasing the temperature to the permanent shape, which, although having a larger wall thickness, but correspondingly a shorter length of the cylinder and / or diameter of the cylinder. By thickening the wall, the material located in the cavity of the cylinder is fixed and, if necessary, sealed against a material located outside the cylinder, since the cylindrical shaped body, due to the thicker wall in the permanent shape, the space between the material in the cavity of the cylinder and the material on the outer surface of the cylinder, ie fills outside the cylinder and thus seals. The cylindrical shaped body according to the invention preferably has a length of 5 mm to 500 mm and a diameter of 4 mm to 300 mm. The hollow space of the cylindrical shaped body preferably has a diameter of 2 mm to 100 mm.

Thermoplastic polyurethanes and processes for their production are generally known and have been described in many different ways. The TPUs according to the invention preferably have an at least partially crystalline soft phase. TPU are characterized by good ones

Strengths, abrasion, tear propagation resistance and chemical resistance, and can be produced in almost any hardness by suitable raw material composition. In addition, TPUs offer the advantage of cost-effective production, for example by the belt or reaction extruder process, which can be carried out continuously or batchwise, and the simple processing of thermoplastics. The production of hollow cylindrical shaped articles from the thermoplastic polyurethane, for example by means of extrusion, is generally known to the person skilled in the art.

The preparation is usually carried out by reacting (a) diisocyanates, in the present case preferably aliphatic diisocyanates, with (b) compounds which are reactive towards isocyanates and have a molecular weight of 500 g / mol to 8000 g / mol, if appropriate in the presence of (c) chain extenders with a molecular weight of 60 g / mol to 499 g / mol, (d) catalysts and / or (e) customary auxiliaries.

To adjust the hardness of the TPUs, the build-up components (b) and (c) can be varied in relatively wide molar ratios. Molar ratios of component (b) to chain extenders (c) to be used in total from 1: 0.5 to 1: 8, in particular from 1: 1 to 1: 4, have proven useful, the hardness of the TPUs increasing with the content of (c) increases. The implementation for the production of the TPU can take place with a key figure of 0.8 to 1.2: 1, preferably with a key figure of 0.9 to 1: 1. The characteristic number is defined by the ratio of the total isocyanate groups of component (a) used in the reaction to the groups reactive towards isocyanates, i.e. the active hydrogens, components (b) and optionally (c) and optionally monofunctional isocyanate-reactive components as chain terminators, such as Monoalcohols. The thermoplastic polyurethanes are usually produced in a one-shot or prepolymer process on the belt system or on the reaction extruder. The components (a), (b) and (c) and, if appropriate, chain terminators which come to the reaction are combined together or in a specific order and brought to reaction. In the reaction extruder process, the build-up components (a) to (c) and, if appropriate, chain terminators, (d) and / or (e) are introduced into the extruder individually or as a mixture, e.g. reacted at temperatures of 100 to 250 ° C, preferably 140 to 220 ° C, the TPU obtained is extruded, cooled and granulated. The TPU molded articles can be produced by generally known processes.

The components (a), (b), (c) and, if appropriate, (d) and / or (e) which are normally used in the production of the TPUs are to be described by way of example below:

(a) Aliphatic, cycloaliphatic, araliphatic and / or aromatic diisocyanates can be used as isocyanates, usually diisocyanates. The following aromatic isocyanates may be mentioned as examples: 2,4-tol (u) ylene diisocyanate, mixtures of 2,4- and 2,6-tolylene diisocyanate, 4,4'-, 2,4'- and / or 2,2'-diphenylmethane diisocyanate, mixtures of 2,4'- and 4,4'-diphenylmethane diisocyanate, urethane-modified liquid 4,4'- and / or 2,4'-diphenylmethane diisocyanates, 4,4'-diisocyanatodiphenylethane (1,2) and 1,5-naphthylene diisocyanate. As aliphatic diisocyanates (a), customary aliphatic and / or cycloaliphatic diisocyanates are used, with for example tri, tetra, penta-, hexa-, hepta- and / or octamethylene diisocyanate, 2-methyl-pentamethylene-diisocyanate-1, 5, 2-ethyl-butylene-diisocyanate-l, 4, 1-isocyanato- 3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophorone diisocyanate, IPDI), 1,4- and / or 1,3-bis (isocyanatomethyl) cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, l-methyl-2, 4- and / or -2, 6-cyclohexane diisocyanate, 4,4'-, 2,4'- and / or 2,2 '-dicyclohexylmethane diisocyanate. Hexamethylene-1, 6-diisocyanate (hexamethylene diisocyanate, HDI) and / or 4,4'-, 2,4'- and / or 2,2'-diphenylmethane diisocyanate (MDI) is preferred as isocyanate (a ) used.

(b) As isocyanate-reactive compounds (b), generally known polyhydroxyl compounds with molecular weights of 500 g / mol to 8000 g / mol, preferably 800 g / mol to 6000 g / mol, in particular 2000 g / mol to 4000 g / mol, and preferably an average functionality of 1.8 to 2.6, preferably 1.9 to 2.2, in particular 2, for example generally known polyesterols, polyetherols and / or polycarbonate diols.

Preferably used as (b) ε-caprolectone and / or polyester diol based on adipic acid and butane-1,4-diol and / or hexane-1,6-diol as the diol component, the ratio of butane-1,4- diol and hexane-1,6-diol can be selected depending on the desired melting point of the soft phase and the desired crystallinity of the soft phase.

(c) Generally known compounds can be used as chain extenders (c), for example diamines and / or alkanediols having 2 to 10 carbon atoms in the alkylene radical, in particular ethylene glycol and / or 1,4-butanediol, and / or hexanediol and / or di - and / or tri-oxyalkylene glycols with 3 to 8 carbon atoms in the oxyalkylene radical, preferably corresponding oligo-polyoxypropylene glycols, it also being possible to use mixtures of the chain extenders. 1, 4-bis (hydroxymethyl) benzene (1,4-BHMB), 1, 4-bis (hydroxyethyl) benzene (1,4-BHEB) or 1,4-bis (2 -hydroxyethoxy) -benzene (1,4-HQEE) are used. Ethylene glycol, butanediol and / or hexanediol are preferably used as chain extenders.

(d) Suitable catalysts, which in particular the reaction between the NCO groups of the diisocyanates (a) and the

Accelerate hydroxyl groups of the structural components (b) and (c) are those known in the prior art and customary tertiary amines, such as, for example, triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N, N'-dimethylpiperazine, 2- (dimethylaminoethoxy) ethanol, diazabicyclo [2/2/2] octane and the like, and in particular organic metal compounds such as titanium acid esters, Iron compounds such as iron (III) aσetylacetonate, tin compounds, for example tin diacetate, tin dioctoate, tin dilaurate or the tin dialkyl salts of aliphatic carboxylic acids such as dibutyltin diacetate, dibutyltin dilaurate or the like. The catalysts are usually used in amounts of 0.0001 to 0.1 part by weight per 100 parts by weight of polyhydroxy compound (b).

(e) In addition to catalysts, customary auxiliaries (e) can also be added to the structural components (a) to (d). Examples include surface-active substances, glass fibers, flame retardants, nucleating agents, lubricants and mold release agents, dyes and pigments, inhibitors, stabilizers against hydrolysis, light, heat, oxidation or discoloration, protective agents against microbial degradation, inorganic and / or organic fillers, reinforcing agents and plasticizers. Additives are also mentioned which lead to an improvement in adhesion between TPU and wood, particle board or wood substitutes, specifically in this invention. Such adhesion promoters can e.g. Additives containing isocyanate.

Auxiliaries or additives mentioned can be added to the TPU directly during synthesis or only during thermoplastic processing in bulk or incorporated in a carrier, e.g. TPU, can be added as so-called masterbatches.

In addition to the raw materials (a) to (e) mentioned, chain terminators with a molecular weight of 46 to 499 can also be used. Such chain terminators are compounds that have only one isocyanate-reactive functional group, such as Monoalcohols. The flow behavior can be specifically adjusted by means of such chain terminators.

More detailed information on the above-mentioned auxiliaries and additives can be found in the specialist literature. All molecular weights mentioned in this document have the unit [g / mol] and represent the number average molecular weight. example

Thermoplastic polyurethane based on hexamethylene diisocyanate, a polyester diol from adipic acid and butanediol as well as the short-chain diol butanediol was extruded through a tube profile die into hollow bodies with an inner diameter of 4mm and a wall thickness of 1.20mm. This "permanent" shape of the tube was expanded at room temperature to an inner diameter of 5 mm using a metal mandrel and thus converted into the "temporary" shape. The wall thickness of the cylindrical shaped body was reduced by approx. 10% to 1.1 mm. At a storage temperature of 60 ° C, the "temporary" shape of the tube pattern was returned to the "permanent" shape within 2 minutes

Claims

claims

1. Hollow cylindrical shaped body based on thermoplastic polyurethane in a temporary shape, characterized in that the wall of the hollow cylindrical shaped body in the permanent shape has a thickness which is at least 10% greater than the thickness of the wall of the hollow cylindrical shaped body in the temporary form.

2. Shaped body according to claim 1, characterized in that the permanent shape is the shape of the shaped body which is present at a temperature in the range greater than or equal to the melting temperature of the soft phase and the lower melting temperature of the hard phase.

3. Shaped body according to claim 1, characterized in that the temporary shape is the shape of the shaped body which is below the melting temperature of the soft phase and by heating the shaped body to a temperature in the range greater than or equal to the melting temperature of the soft phase and low melting temperature of the hard phase the temporary form can be converted into the permanent form.

4. Shaped body according to claim 1, characterized in that the wall of the shaped body in the temporary shape has a thickness of

1 mm to 100 mm.

5. Shaped body according to claim 1, characterized in that the thermoplastic polyurethane on the reaction of isocyanates with ε-caprolactone and / or polyester diol based on adipic acid and butane-1,4-diol and / or hexane-1,6 -diol based as a diol component.

6. Shaped body according to claim 1, characterized in that the thermoplastic polyurethane is based on hexamethylene diisocyanate as the isocyanate component.

7. A method for fastening or sealing materials, characterized in that a material is placed in the cavity of the shaped body according to claim 1 and then the shaped body according to claim 1 by heating to a temperature in the range greater than or equal to the melting temperature of the soft phase and low melting temperature the hard phase from the temporary form to the permanent form.

8. A method for producing a shaped body according to claim 1, characterized in that the shaped body, starting from the permanent shape, the wall thickness of which is at least 10% greater than the thickness of the wall in the temporary shape, by stretching or rolling at a temperature in the region greater than or equal to the melting temperature of the soft phase and the lower melting temperature of the hard phase is converted into the temporary form and cools in this temporary form to a temperature lower than the melting temperature of the soft phase.