RU2287001C1 - Thermoglue for gluing and hermetic sealing - Google Patents

Abstract

FIELD: gluing materials.

SUBSTANCE: invention relates to thermoglues or glue-melts used for gluing or hermetic sealing of pipelines made of polyolefins, gas-petroleum pipelines, electric cable butt-joining units in cable industry, for gluing polymeric roofing materials, in homes and other branches of industry. Proposed glue comprises copolymer of ethylene with vinyl acetate representing a mixture of copolymer of ethylene with vinyl acetate with the content of vinyl acetate links 10-14 wt.-% and copolymer of ethylene with vinyl acetate with the content of vinyl acetate links 21-24 wt.-%, or copolymer of ethylene with vinyl acetate with the content of vinyl acetate links 26-30 wt.-% taken in the ratio from 1:2 to 1:4, respectively, a mixture of colophony or its derivatives with hydrocarbon resin as a stickiness agent taken in their ratio from 1:0.5 to 1:2.0, respectively, plasticizing agent and, additionally, stabilizing agent and filling agent. Invention provides the necessary physicochemical indices in gluing difficultly adhering articles made of polyolefins, polymeric rolled materials to different substrates in broad range of temperatures and safety exploitation of articles under conditions sign-variable cyclic tensions.

EFFECT: improved and valuable properties of glue.

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Description

The invention relates to hot-melt adhesives or hot-melt adhesives used for bonding various surfaces (polymeric materials and products, metals, glass, wooden products, fabrics, paper, etc.), and specifically relates to tape hot-melt adhesives used for bonding and sealing pipelines from polyolefins during their manufacture and assembly, for gluing polymer roofing materials, gluing and sealing the electrical cable docking unit in the cable industry, for anticorrosive protection of gas, water, and oil pipelines and in others.

Hot melt adhesives are commonly referred to as thermoplastics, which go into a viscous flow state when heated and harden again when cooled. The most widespread hot melt adhesives based on copolymers of ethylene with vinyl acetate with a vinyl acetate content of from 15 to 40 wt.%. They have good adhesion to many substrates, are well compatible with other components of adhesives, have the greatest stickiness and frost resistance. To increase adhesion characteristics, rosin is introduced into hot melt adhesives in amounts of 35-45 wt.%. Hot melt adhesives based on EVA copolymers adhere well aluminum foil, kraft paper, polyethylene, but for the most part they do not have increased heat resistance, stiffness and adhesion to most substrates under severe operating conditions of glued materials and products (D.A. Kardashov, A. P. Petrova, "Polymer adhesives", M., Chemistry, 1983, p.95-96).

To improve technological and operational properties, various additives are introduced into hot melt adhesives based on EVA copolymers.

From RU 665701, 01/10/1996, a hot melt adhesive based on a copolymer of ethylene with vinyl acetate with a content of vinyl acetate groups of 10-30%, with the addition of an adhesive additive (stickiness agent - rosin, rosin glycerol ester), plasticizer (dibutyl phthalate, dioctyl phthalate, dioctylsebacate, is known) paraffin), and in which polyethylene oxide with M.M. is additionally added to increase adhesion to various materials and lower the temperature of thermal activation. 750000-1000000.

The obtained glue can be applied on a paper base at a temperature of 130-150 degrees C. When receiving heat-sensitive tapes with an adhesive layer, the surface of the layer is subjected to treatment with volvovinyl; heat-sensitive paper tape was activated at 80-100 ° C and glued to the surface of various substrates. The glue provides resistance to peeling of the paper tape from steel 0.35-0.55 kgf / cm, aluminum 0.39-0.45 kgf / cm, polyethylene 0.35-0.41 kgf / cm. However, this well-known adhesive can only be used for bonding polymer film materials in the furniture industry, paper and cardboard in the printing industry and to obtain heat-sensitive packaging and labeling tapes.

Another hot melt adhesive is known from RU 2112005, 05.27.1998, containing a copolymer of ethylene with vinyl acetate with a vinyl acetate content of 5-24 wt.%, Styrene-butadiene thermoplastic elastomer, rosin glycerol ester (stickiness agent), stabilizer (for example: 2,2-methylene - (6-tert-butyl-4-methylphenol)), in which paraffin and terpene oil are additionally added. Moreover, as an EVA copolymer, it contains an EVA copolymer with a vinyl acetate content of 10-14%, or an EVA copolymer with a vinyl acetate content of 21-24%. This glue, however, is intended for use in the printing industry in the manufacture of books by the method of seamless binding and ensures the durability of the adhesive bonding of book blocks.

Hot melt adhesives are also used for adhesive tapes. As a rule, in this case, they include the following components: a binder (in most cases elastomers), a stickiness agent (rosin derivatives and terpene resins), a plasticizer, a stabilizer, an antioxidant; most often, ethylene vinyl acetate copolymers are used for such adhesives. Sticky tapes are materials consisting of a backing and a sticky adhesive layer. As a base, various film materials are used (polyethylene, cellophane, polyvinyl chloride, foil, paper, fabrics, rubbers, plastic compounds). The surface of the substrate before applying the adhesive can be activated by chemical means, machining, etc .; upon receipt of adhesive tapes, in order to avoid sticking of the tape when winding in a roll, the adhesive layer is duplicated with a polymer film or paper. Hot melt adhesives are applied to the base by extrusion, melting and rolling, spraying through a nozzle, extruding glue monofilaments onto the base (D. A. Kardashov, A. P. Petrova, “Polymer adhesives”, M., Chemistry, 1983, pp. 97,145 -146).

A hot melt adhesive for the production of adhesive tapes is known from SU 1147732, 03.30.1985, containing styrene-butadiene-thermoplastic elastomer, liquid carboxyl-containing nitrile butadiene rubber, low molecular weight polyisobutylene with M.M. 10000-20000, a copolymer of ethylene with vinyl acetate with a content of vinyl acetate units of 17-33%, stickiness agent (rosin, its esters, polyterpene, phenol-formaldehyde resins, coumaronindene resins), plasticizer (phthalic and sebacic acid esters). This glue has a high resistance to steam, salt spray and polymer varnishes, as well as high adhesive performance, but is intended mainly for labeling and packaging of appliances, products and equipment. The glue is applied evenly on paper or other substrates by extrusion at 200 ± 10 degrees C and protected with release paper.

From SU 523925, 11/30/1976 a temperature sensitive roll adhesive is known, consisting of a reinforcing substrate coated with a layer of a copolymer of vinyl acetate with dibutyl maleate, and on one or two sides it is additionally coated with a layer of polyvinyl alcohol readily soluble in water to prevent self-sticking of the material in the roll, however, This adhesive material is intended only in the printing industry for bonding cliches and stereotypes.

From SU 747870, 07.15.1980, an adhesive for adhesive tapes with a polyethylene backing is known for insulating gas and oil pipelines in everyday life. The glue contains low molecular weight polyisobutylene, high molecular weight polyisobutylene, butyl rubber, an adhesive additive (stickiness agent is rosin glycerol ester, polyterpene resin, PFS, 101 "K" resin), a condensation product of methylsilantriol and phenylsilantriol and a solvent (mixture of gasoline). The glue has good adhesion and cohesion properties, but it refers to toxic and fire hazardous products due to the presence of a sufficiently large amount of solvent in its composition, i.e. does not apply to hot melt adhesives, which limits its use.

From SU 861380, 09.09.1981, a hot melt adhesive is known for the production of paper and polymer-based adhesive tapes, containing a copolymer of ethylene with vinyl acetate with a vinyl acetate content of 11-45 wt.%, An adhesive additive (sticking agent) - a mixture of extraction rosin and glycerin rosin ether , the plasticizer is dioctyl phthalate and, possibly, an antioxidant (Neozone A or D, hydroquinone, pyragallol). The glue has good adhesion and cohesion properties, but is mainly intended for labeling, marking, gluing roll material in processing, sealing containers.

According to the technical nature and the achieved result, the above-described known hot melt adhesive for the production of adhesive tapes (roll adhesive material) according to SU 1147732 is closest to the claimed invention.

The technical task of the claimed invention is to provide the required physical and mechanical characteristics when gluing hard-to-bonded products from polyolefins, polymer roll materials to various substrates in a wide temperature range and reliable operation of the products under alternating cyclic stresses.

The stated technical problem is achieved in that the hot melt adhesive comprising a copolymer of ethylene with vinyl acetate, a sticky agent and a plasticizer, contains as a polymer binder a mixture of a copolymer of ethylene with vinyl acetate with a content of vinyl acetate units of 10-14 wt.% With a copolymer of ethylene with vinyl acetate with a content of vinyl acetate units 21-24 wt.% Or with a copolymer of ethylene with vinyl acetate with a content of vinyl acetate units of 26-30 wt.% With a ratio of respectively from 1: 2 to 1: 4, as a stickiness agent, a mixture of rosin or its roizvodnyh with a hydrocarbon resin in their ratio of 1: 0.5 to 1: 2.0, respectively, and additionally a plasticizer, a filler and a stabilizer in the following ratio in wt.%:

Vinyl Acetate Ethylene Copolymer vinyl acetate units 10-14 wt.% 8-15 Vinyl Acetate Ethylene Copolymer vinyl acetate units 21-24 wt.% or ethylene vinyl acetate copolymer containing vinyl acetate units 26-30 wt.% 24-40 Rosin or its derivatives 15-30 Hydrocarbon resin 15-30 Plasticizer 3-12 Stabilizer 0.2-1.0 Filler rest

The hot melt adhesive according to the invention contains various derivatives of rosin (escaped esters, hydrogenated or disproportionate rosin) as rosin esters, for example, rosin glycerin ester; as a hydrocarbon resin, for example, an indene-coumarone resin, a polyterpene resin, various aliphatic and aromatic petroleum polymer resins, as a plasticizer, oligomeric (low molecular weight) rubbers, for example, polyisobutylene with M.M. 5000-20000, paraffin, dibutyl phthalate, dioctophthalate, dioctyl sebacinate; as filler - chalk, soot, titanium dioxide, zinc oxide, aerosil; as a stabilizer, for example phenolic type stabilizers, in particular 2,2'-methylene - (6-tert-butyl-4-methylphenol, various herganox-4,4'-butylidenebis (2-tert-butyl-5-methylphenol), N-phenyl -N-isopropyl-n-phenylenediamine and others.

Hotmelt is prepared, for example, by the following technology. A mixture of rosin or its ether with a hydrocarbon resin, a plasticizer and a stabilizer are loaded into a mixer with a Z-shaped mixer preheated to 135-150 ° C. At the end of the melting of the stickiness agents, a mixture of ethylene vinyl acetate copolymers is loaded into the mixer and mixed for 40-50 minutes until a homogeneous mixture is obtained. Next, fillers are introduced into the mixer and the contents of the mixer are further mixed for 20-30 minutes. Table 1 presents examples of the compositions of the hot melt adhesive according to the invention, and table 2 presents the main physical, technical and operational properties.

Table 1.
Examples of hot melt adhesive compositions of the invention. Name of components The content of components in wt.% According to examples one 2 3 four 5 1. A copolymer of ethylene with vinyl acetate (EVA) containing vinyl acetate units (VA) - 10-14 wt.% 10 8 12 fifteen fifteen 2. The EVA copolymer with the content of VA units - 21-24 wt.% - 26 40 - - 3. The EVA copolymer with the content of VA units - 26-30 wt.% 40 - - 35 thirty 4. Sticking agent: - rosin twenty - twenty - fifteen rosin glycerin ester - 27.6 - thirty - - hydrocarbon resin brand Picotac (aliphatic) - 26 18.5 - thirty - petroleum resin fifteen - - fifteen - 5. Plasticizer: - low molecular weight. polyisobutylene 7 12 5 - 5 - dioctylsebacinate - - - 3 - - paraffin 3 - - - - 6. Phenolic type stabilizer: brands Irganox 1010 0.2 - 0.5 - 0.8 Brands Diafen FP - 0.4 - 1,0 - 7. Filler: - titanium dioxide 4.8 - - - - - soot - - 5 - 3.0 - aerosil - - - 1,0 1,2

Table 2.
Properties of hot melt adhesive according to the invention. Names of indicators Example Properties one 2 3 four 5 1. Softening point, ° C 78 60 90 88 85 2. Conditional tensile strength, MPa 3.2 2,8 3,1 2.9 3.0 3. The relative elongation at the time of rupture,% 750 950 800 700 820 4. Shear strength, MPa - polyethylene / polyethylene 3.4 3.0 3.2 3.0 3.6 - metal / metal 3.6 3.4 3,5 3,7 3,5 5. Water absorption in 24 hours,% 0.2 0.1 0.17 0.15 0.2 6. Frost resistance, ° C, not higher -thirty -35 -twenty -25 -25 7. Appearance elastic white tape sticky tape light brown colors black tape (has residual stickiness) gray ribbon black elastic tape

A high degree of reliability of bonding using hot melt adhesive according to the invention and sealing of the pipe docking assembly was confirmed during an express assessment of the performance of couplings under alternating cyclic loads for compliance with the requirements of the European standard EN 489.

The load test is carried out in a sandbox simulating the occurrence of a pipeline underground at a depth of 2.5 meters with the cyclical movement of the coupling in a layer of sand with an amplitude of 50 mm / min.

Coupling samples withstood at least 1000 test cycles, which corresponds to the required 30 years of heat conduit service. Further tests showed that the clutch retains its integrity for more than 5000 cycles.

The following is an example of the use of the hot melt adhesive according to the invention in the form of tape adhesive material for insulation of a heat conduit joint.

The pipeline consists of a steel pipe - the core and the outer shell of linear polyethylene, the space between which is insulated with polyurethane foam.

A heat-shrink sleeve of radiation-crosslinked polyethylene is installed on the outer polyethylene sheath before welding a steel pipe. Insulation work begins after quality control of the weld of the steel pipe.

On the surface of the outer polyethylene sheath on both sides of the joint due to residual stickiness, a hot-melt adhesive tape according to the invention is glued. The edges of the coupling are seated by the soft flame of a gas burner at a temperature of 115-130 ° C. At the same time, due to the melting of hot melt adhesive, gluing and sealing of the joint occur simultaneously. The tightness control is carried out by crimping the joint with compressed air.

Upon completion of the shrinkage of the coupling, gluing and sealing of the docking unit, the joint is insulated by pouring a mixture of polyurethane foam components into the space under the coupling. The filling hole is closed by a drain plug. After the foam has hardened, the drainage plug is removed and the filling hole is closed with a polyethylene plug. The finished insulated joint is barrel-shaped.

Claims (1)

Hot-melt adhesive for sealing and sealing, including a copolymer of ethylene with vinyl acetate, a sticky agent, a plasticizer, characterized in that it contains a mixture of a copolymer of ethylene and vinyl acetate with a content of vinyl acetate units of 10-14 wt.% And a copolymer of ethylene with vinyl acetate with a content of vinyl acetate units 21-24 wt.% or a copolymer of ethylene with vinyl acetate with a content of vinyl acetate units of 26-30 wt.%, with a ratio of respectively from 1: 2 to 1: 4, as a sticking agent, a mixture of rosin or its derivatives with a hydrocarbon resin at their ratio is from 1: 0.5 to 1: 2.0, respectively, and additionally a stabilizer and a filler in the following ratio of components, wt.%: Ethylene Vinyl Acetate Copolymer with a vinyl acetate content of 10-14 wt.% 8-15 Ethylene Vinyl Acetate Copolymer with a vinyl acetate content of 21-24 wt.% or a copolymer of ethylene with vinyl acetate with a vinyl acetate content of 26-30 wt.% 24-40 Rosin or its derivatives 15-30 Hydrocarbon resin 15-30 Plasticizer 3-12 Stabilizer 0.2-1.0 Filler Rest