MXPA00006544A - Insulation protection tape - Google Patents

Abstract

An insulation protection film useful in a comprise a two-phase thermoplastic elastomer blend comprising a continuous phase and a particulate phase, and a flame retardant wherein the film substrate has a storage modulus of at least 107 Pascals up to about 150°C.

Description

Insulation Protective Tape Field of the Invention The present invention relates to a film substrate of two-phase thermoplastic elastomer for an adhesive, and to an adhesive tape comprising a film substrate with a non-polyvinyl chloride backing, which adheres well to itself and to the insulation of the tubes on steel pipes, in addition to presenting excellent properties in both cold and high temperatures.

Background of the Invention In industries that have large pipelines for the transport of liquids or gases, such as the petrochemical industry, the tubes are often made of stainless steel or other metals prone to corrosion. Typically, the pipes are coated with an insulation that can be made of various materials, such as polyurethane foam, ceramic foam, fibrous materials, fiberglass or the like. Other possible layers Ref: 121021 includes an anticorrosive coating on the pipe, and a barrier layer against water vapor on the insulation, to prevent the latter from entering. In general, the element that protects against corrosion and that is placed on top of them has been a metallic coating. Said coating is constituted by preformed pieces of stainless steel or aluminum (in the form of T, elbows, fixing structures, etc.) and sent to the place of installation. The preforms are placed on the insulation (as well as other layers mentioned above, if applicable) and if they are fixed together with steel bands or rivets and screws. The seams in the coating are usually caulked with a silicone compound. This system presents many difficulties; its processing is expensive, as is transport and installation. In addition, the coating lacks flexibility, which can cause problems if any distortion occurs in the coatings such as that caused by irregularities in the surface of the pipe, or by an inaccurate adjustment. In this case the seams tend to open, not being able to close again, which allows the entry of water and other contaminants. Likewise, the coating itself is subject to correction.

The polymeric materials are flexible and it is convenient to use them as insulation protection layers for various applications of which it is necessary to have flame retardant capacity. Using a material of this type together with an adhesive would achieve a reduction of the expense and labor, as well as greater security in the facilities, as well as ease of re-entry and flexibility. But it is necessary that there is adhesion capacity at low temperatures and stability at high temperatures. A variety of efforts have been made to improve flame retardancy or adhesion of these materials, especially at extreme temperatures. However, a large number of materials exhibit poor dimensional stability at high temperatures, and less flexibility and / or adhesion at low temperatures.

It is known that it is possible to make the thermoplastic polymers flame retardants by adding organohalide compounds, such as those disclosed in U.S. Patent No. 3,530,164. However, one of the problems with regard to the use of these compounds, is that they migrate through the polymer and enflorecen to the surface where the exudate is translated into an aesthetically unpleasant nuance. Obviously, this fluorescence also results in loss of flame retardation. A second problem is dripping, if the polymer melts during contact with the flame. Finally, many applications require that the materials used do not have polyvinyl chlorides, for environmental and / or safety reasons.

WO 9729153 discloses a thermoplastic elastomer composition which, when used, at least as an internal layer of a hose, improves flexibility, oil resistance and low temperature properties.

U.S. Patent No. 5,300,356 discloses a wrapping tape system for protecting metal conduits and pipes against oxidation and comprises a first coating, an inner shell and an outer shell. The inner shell is a polyolefin layer with adhesive on the inner surface and a heat-fusible material on its outer surface, and the outer shell is an impact resistant polyolefin layer, which has a heat fuse layer in one or both surfaces. The heating melts the inner wrapper and the outer wrap to achieve a protective and continuous closed coating.

U.S. Patent No. 5,017,637 discloses thermoplastic fire retardant compounds which are chemically crosslinked and comprise 5-60% olefin copolymers, 1-15% organ polysiloxane and 20-85% flame retardant. . Preferred embodiments include a copolymer and an additional ethylene elastomer or copolymer. Preferred elastomers are copolymers of EP or EPDM. Ethylene vinyl acetate is also disclosed. As the flame retardant compound, metal oxide hydrates are used.

U.S. Patent No. 4,772,642 discloses a resin containing polyolefins, preferably polypropylene. For the flame retardation, ammonium polyphosphate particles are used, and the particles are encapsulated by a melamine resin.

Patent EP 274,888 discloses a halogen-free flame retardant elastomer composition, which contains inorganic filler, in more than one fifty%. It does not mention the addition of a coupling agent.

Patent JP 04,139,241 discloses an olefin resin • mixed with ammonium polyphosphate, a silane coupling agent, and olefinic synthetic rubber and a petroleum resin. Vinyl trimethoxylan is given as an example of the silane. The advantages of this compound are a high electrical resistance and high resistance to bleeding.

US Patent No. 5,130,357 discloses a flame retardant composition containing polypropylene as the main constituent, a silane coupling agent, and / or olefin synthetic rubbers, ammonium polyphosphate (APP) or melamine modified APP, and one or more compounds of nitrogen, as well as optionally, polyethylene resin, crosslinking agent and thiophosphate.

U.S. Patent Nos. 4,808,474 and 4,769,283 disclose a film substrate of pressure-sensitive adhesive tape with improved toughness, comprising blends of crystalline isotactic polypropylene and compatible flexible polymers (in the latter) or compatible polymers containing ethylene (in the first) whose polymers include EPDM and / or EVA.

U.S. Patent No. 4,985,024 discloses a film substrate of pressure sensitive and biodegradable adhesive tape, which comprises said blend, combined with an unsaturated elastomer.

The patent of the United States of America No. 4,910,639 discloses a biaxially oriented film, suitable for use as an electrically insulating film. The film is composed of polyolefins and contains carbonate particles as a neutralizing agent.

U.S. Patent No. 4,594,390 discloses a thermoplastic elastomer comprising a mixture of plastic and cured rubber produced by chewing during vulcanization at a cut-off range of at least 2000 sec-1. These compositions may include other ingredients such as fillers, carbon black, clay, silica, plasticizers and the like.

It has now been discovered that an adhesive tape formed of adhesive coated on a film substrate containing a two-phase thermoplastic elastomer, together with a flame retardant, offers excellent insulation protection generally used around the steel pipe, even when undergoes extreme low temperatures. The film substrate also exhibits excellent stability at high temperature. Likewise, the film substrate and the tape of the invention have advantages with respect to the products currently available and that use polyvinyl chloride as the main ingredient in their substrates.; the amount of corrosive gases released with combustion and the water vapor transmission rates are reduced, while the flame retardancy capacity is maintained and properties at extreme temperature are improved.

Brief Description of the Invention The present invention offers a film substrate useful in forming the backing of an adhesive tape which provides good adhesion to itself in addition to an excellent flame retardancy, greater flexibility at low temperature and dimensional stability at high temperature.

Specifically, the film substrates of the invention comprise a mixture of thermoplastic elastomer in two phases, comprising a continuous phase and a particulate phase, plus a flame retardant, the film substrate having a storage module of at least 107 Pascals up to 150. ° C.

The film substrate of the invention comprises a mixture of thermoplastic elastomer in two phases, presenting a continuous phase formed of a polyolefin selected from polypropylene or polyethylene and mixtures thereof, and a particulate phase formed of a copolymer formed of monomers selected from the group It consists of ethylene, propylene and diene monomers.

The adhesive tapes of the invention comprise an adhesive coating applied in a layer on a film substrate having a composition comprising a thermoplastic elastomer mixture of at least two phases and at least one flame retardant.

Preferred tapes of the invention require that the composition of the film substrate include a blend of thermoplastic elastomer that is selected from blends having a continuous phase formed of a polyolefin selected from polypropylene or polyethylene and a particulate phase formed from a copolymer formed of monomers selected from the group consisting of ethylene, propylene and dienes.

Most preferred tapes have a film substrate containing a thermoplastic elastomer mixture which contains a reduced amount of water-leachable chlorides.

The terms used here have the following meanings: 1. The term "leachable" means that a chemical compound is not bound and will be dragged out of the composition by a solvent such as water. 2. The term "adhesive" refers to a sticky medium that holds a tape in place. 3. The terms "mouldable" and "mouldable" refer to the ability of the belt to make an essentially complete contact with the surface of an irregular object or to bend. 4. The term "insulation tape" refers to a tape that is applied over layers of insulation surrounding a pipe, in order to protect the pipe against corrosion, and / or insulation against mechanical damage, contamination, water transmission and Similar.

All the percentages, parts and relationships indicated here are by weight, unless specifically noted otherwise.

Detailed description of the invention.

The film substrates of the invention comprise a two phase thermoplastic elastomer blend. Among the thermoplastic unit elastomers are polyolefins such as polypropylenes, polyethylenes and the like. These thermoplastic elastomer blends comprise a continuous phase and a particulate phase. The continuous phase should include at least one polyolefin, preferably polypropylene or polyethylene. The particulate phase includes copolymers formed of ethylene, propylene and diene monomers, preferably ethylene propylene, ethylene propylene diene terpolymers, and the like. Commercially available examples include Santoprene®, from Advanced Elastomers Systems, "Alt 8000" available from Alternative Rubber and Plastics, and Uniprenne® available from Teknor Apex.

In an embodiment of the film substrates and adhesive tapes of the invention, the thermoplastic elastomers useful in the film substrate have a low content of water-leachable chlorides. Specifically, elastomers having less than 100 ppm, and better, less than 90 ppm, water-leachable chlorides, are more useful in this application, since the tapes will be able to leach the chlorides either into the environment or through the adhesive towards the insulation, and through the insulation towards the pipe itself. The leachable chlorides present problems regarding toxicity, health, and corrosion of the materials that are supposed to be protected by the tapes, and this point is of special concern in the piping of pipes for the petrochemical industry and the like.

The thermoplastic elastomer mixture constitutes 45% to 75% of the substrate composition, preferably 60% to 75% by weight of the film substrate composition.

The film substrates of the invention exhibit good flexibility and the adhesive tapes using said substrate exhibit good adhesion even under low temperature conditions for example 0 ° C or -18 ° C.

The film substrates of the invention also exhibit excellent dimensional stability as compared to conventional polyvinyl chloride substrates. When the film is subjected to high temperature the storage module (E ") does not decrease significantly in its value, but remains above 107 Pascal at temperatures from -150 ^ 0 to 150 ° C. The conventional film substrates made with chloride of polyvinyl, and the tapes made with them, have storage modules that fall below 107 Pascal at 100 ° C, and 106 Pascal at 150 ° C.

Similarly, the film substrate contains at least one flame retardant. In cases where non-halogenated flame retardants are recommended, useful include those based on phosphorus, such as ammonium polyphosphate, melamine phosphate and / or red phosphorus. For example, there is availability of flame retardants under the trade names Exolit® IFR-23, comprising ammonium polyphosphate in the mixture with a variety of coagents, fillers and pigments.

EP 0204027 discloses other suitable flame retardants, and comprise mixtures of ammonium polyphosphate, melamine cyanurate and a hydroxyalkylene derivative of isocyanuric acid, at least partially in the form of a homopolymer. There are examples of these materials commercially available under the trademark Masterflem®. Other suitable flame retardants comprise oligomeric phosphorus / nitrogen flame retardants containing a triazine core, used in conjunction with ammonium polyphosphate, and polyphosphonamine derivative used in conjunction with ammonium polyphosphate. Other useful classes are the phosphate salts of polyols, such as pentaerythritol, for example, Great Lakes CN1197, and flame retardants of aluminum hydrate, which are widely available.

Preferred film substrates of the invention contain a brominated flame retardant. Among the useful brominated flame retardants are ethylene bis (t and rhabromophthalimine), decabromodiphenyl oxide and tet rhabromocyclooctane and the like. Commercial additions include Saytex® flame re-delays, available from Albemarle Corporation, including Saytex® 8010 and Saytex® BT-93W. Preferred compositions for the film substrate comprise from 5% to 25% of brominated flame retardant.

To further improve the flame retardancy in the compositions using brominated flame retardants, various synergists of metal compound, such as alkaline earth metal oxides, such as barium oxide, magnesium oxide, as well as compounds such as silicon dioxide, titanium dioxide, zinc oxide, aluminum oxide, aluminum oxide trihydrate, antimony oxides, alkaline earth metal hydroxides and the like. When present, these additives generally comprise from 2 to 10 percent by weight of the total composition.

The film substrate also preferably contains at least one filler, such as clay, talc, alumina and the like. Useful fillers include those commercially available as "Mistron" from Luzenac America. The inclusion of a filler of this type helps to prevent dripping during the flame test. Preferred compositions include from 5% to 15% filler.

The compositions of the invention may also incorporate conventional adjuvants such as plasticizers, dyes, pigments, antioxidants, antistatic agents and the like, in amounts such that they do not substantially affect the primary properties of the composition. A preferred helper is a UV stabilizer or mixture thereof. Useful stabilizers include phosphite antioxidants, hindered amine light stabilizers, light benzophenone type absorbers, and mime mixtures. The film substrates of the invention comprise said UV stabilizer at 0.05% to 2%.

The ingredients for the film substrate can be combined using any conventional method such as mixing or blending, followed by a film-forming process, such as grinding, extrusion, rolling or other pouring techniques. Extrusion is a preferred method, single or double screw extruders being useful.

The tapes of the invention have at least one side of the film substrate coated with an adhesive. The adhesive may be any conventional adhesive known in the art, including without limitation, natural rubber adhesives, thermoplastic elastomers, such as block copolymers, hot-melt adhesives, acrylic adhesives, silicone adhesives and the like. The adhesive may comprise conventional additives such as adhesion promoters, plasticizers, pigments, fillers, initiators, crosslinking agents and the like, as desired. The adhesive is applied to the film substrate using conventional coating means.

In a preferred embodiment, the adhesive is of the mastic type, comprising at least one compound selected from polyisobulene, aliphatic hydrocarbon resins, butyl acrylate, or the like, and at least one flame retardant compound, which may be brominated or not halogenated, as desired.

The adhesive tape of the invention is useful to offer protection to the insulation covers on metal pipes and which are also called "chamfered". The tape can also be processed in widths from less than 2 cm to 60 cm or more, as desired.

Because of the adhesive tape adheres well to itself and to friable insulation materials such as asbestos, glass fiber and the like, it would likewise be useful to encapsulate such materials for safety, toxicity and convenience reasons, such as Asbestos coating in old buildings.

The examples below are intended to be illustrative and should not be construed as limiting the scope of the invention which is defined solely by the claims. A person skilled in the art could create variations that would be within the spirit of the invention.

Test Methods.

Adhesion Adhesion is the force required to detach a flexible, adhesive-coated sheet material from the test panel, measured at a specific angle and rate of removal. In the examples, this force is expressed as Ne tons per lOOmm of coated sheet width. The procedure followed is thus A strip of the coated 1.27 cm wide sheet is applied to the horizontal surface of a clean glass or stainless steel test plate with a firm contact of at least 12.7 cm linear. A 2 kg hard rubber roller is used to apply the strip. The free end of the coated strip is folded back almost touching, so that the angle of removal will be 180 °. The free end is attached to the scale of the adhesion tester. The test plate is fixed between the jaws of a tensile test machine capable of moving the plate away from the scale at a constant speed of 25.4 centimeters per minute. The reading of the scale in Newtons is recorded as the tape detaches from the surface of the test plate. The data is reported as the average of the range of numbers observed during the test.

Water absorption A previously weighed sample (weight = Wi) is placed in deionized water for 24 hours. After the immersion period the sample is removed, dried by rubbing, and weighed (weight = W2). The percentage of water absorption is [W2-W? ] / ixl 00.

Flammability evaluation. _ This test measures the flammability of the material under an intense heat source as well as the secondary ignition properties. This is the ASTM-1000 test.

A layer of tape is wrapped around a 3,175 mm diameter brass rod which is suspended horizontally. A thin layer of cotton is placed under the sample. A lit Bunsen® burner is held under the tube for 30 seconds. Burning time is measured after removing the flame. To achieve a passing grade, that time is required to be less than 10 seconds and that the cotton can not be ignited, signaling secondary ignition.

Burn Test UL-510.

This is a test according to the ANSI / UL-510 standard, to evaluate self-sustained flame and secondary ignition.

Examples 1 and Experimental IC The adhesive properties of the tape of the invention. They were checked at room temperature and at 0 ° C. Steel adhesion and backing adhesion were tested using ASTM D1000 standards. A summary of the results is indicated in tables 1 and 2.

The example IC is a commercially available corrosion protection tape, which has a film substrate containing polyvinyl chloride, and which uses a mastic adhesive similar to that of example 1.

The adhesion and mechanical properties were checked at room temperature, at 0 ° C and at -18 ° C. As shown in the tables below, the tape using a film substrate of the invention maintained good properties even at low temperatures.

The tape of Example 1 was also subjected to two types of ASTM-D1000 Inflammability Burn Test, the tape was quickly extinguished, passing the test. In four of five trials, the burn time was 1 second or less, and in the fifth the extinction occurred in 1.5 seconds. The details of the UL-510 test and variations are given in Table 4. Due to the thickness of the application of the tape, different geometries were tested; UL 510 requires three laps with half overlap. The most severe conditions, using a single turn without overlapping geometry, were also tested. As can be seen in Table 4 below, the adhesive tape of the invention easily passed all three tests.

Table 1: Adhesion and Elongation Properties at Ambient Temperature Table 2: Adhesion and Elongation Properties at 0 ° C.

Traction and Elongation.

Tensile and tensile tests (T & E) indicate flexibility. Tables 1, 2 and 3 show the data corresponding to the Enlogation; as can be seen, the adhesive tape of the invention retains good linting and breaking strength, in comparison with the conventional material of Example IC containing polyvinyl chloride.

Table 3: Elongation properties at -18 ° C Table 4: Flammability UL-510.

Table Other Substrate Formulations Pelicular Table Answers Measures for others Formtions It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property.

Claims (16)

Claims

1. An insulation tape for insulation of pipes, characterized in that it comprises an adhesive and a substrate comprising a mixture of two-phase thermoplastic elastomer, formed by a continuous phase formed of a polyolefin selected from polypropylene or polyethylene and a particulate phase formed from a copolymer formed of monomers selected from the group consisting of ethylene, propylene and diene monomers, and a flame retardant; where the film substrate has a storage modulus of at least 107 Pascals at temperatures up to 150 ° C, and contains less than 100 ppm of leachable chlorides.

2. An insulation tape according to claim 1, characterized in that the thermoplastic elastomer is a mixture having a continuous phase formed of polypropylene and a particulate phase formed of ethylene propylene diene terpolymers.

3. An insulating protective tape according to claim 1, characterized in that said flame retardant is a non-halogenated flame retardant.

4. An insulating protective tape according to claim 1, characterized in that the brominated flame retardant selected from the group consists of ethylene bis (tet rabromoft alimide), decabromodi phenyl oxide and tetrabromocyclooctane.

5. An insulating protective tape according to claim 4, characterized in that it further comprises a metal synergist compound selected from the group consisting of alkaline earth metal oxides, titanium dioxide, zinc oxide, aluminum oxide, aluminum oxide trihydrate, oxides of antimony and alkaline earth metal hydroxides.

6. An insulation tape according to claim 1, characterized in that it also comprises a filler.

7. A protective tape of insulation according to claim 1, characterized in that the thermoplastic elastomer comprises from 45% to 75% of the composition.

8. An insulating protective tape according to claim 1, characterized in that the brominated flame retardant comprises from 5% to 25% of the composition.

9. The use of an insulating protective tape for sealing pipes of the insulation protective tape, comprising an adhesive, and a substrate comprising a two-phase thermoplastic elastomer mixture, formed by a continuous phase formed of a polyolefin selected from polypropylene or polyethylene and a particulate phase formed of a copolymer formed of monomers selected from the group consisting of ethylene, propylene and diene monomers, and a flame retardant; where the film substrate has a storage modulus of at least 107 Pascals at temperatures up to 150 ° C, and contains less than 100 ppm of leachable chlorides.

10. The use according to claim 9, wherein the thermoplastic elastomer is a mixture having a continuous phase formed of polypropylene and a particulate phase formed of ethylene propylene diene terpolymers.

11. The use according to claim 9, wherein said flame retardant is a non-halogenated flame retardant.

12. The use according to claim 9, wherein the brominated flame retardant selected from the group consists of ethylene-bis (tetrabromophthalimide), decabromodiphenyl oxide and tetrabromoclclooctane.

13. The use according to claim 12, wherein it further comprises a metal synergistic compound selected from the group consisting of alkaline earth metal oxides, titanium dioxide, zinc oxide, aluminum oxide, aluminum oxide trihydrate, antimony oxides and alkaline earth metal hydroxides.

14. The use according to claim 9, wherein it further comprises a filler.

15. The use according to claim 9, wherein the thermoplastic elastomer comprises from 45% to 75% of the composition.

16. The use according to claim 9, wherein the brominated flame retardant comprises from 5% to 25% of the composition.