RU2470973C1 - Method of gluing rubber - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: vulcanised rubber is glued by applying onto surfaces to be glued an adhesive based on polychloroprene rubber nairit NT or nairit DP combined with butyl phenol-formaldehyde resin and a modifier. The modifier is added to the adhesive before application thereof onto the surface, with subsequent drying of the adhesive film at room temperature and contacting the surfaces under a load. The modifier used is modified carbon fibre with size of 2-3 mm. The modified carbon fibre is obtained by pyrolysis of polyvinyl alcohol fibres, which are treated with methyl phosphite borate, at 400°C for 30 minutes and then treating the obtained carbon fibre with a mixture of methyl phosphite borate and triethanolamine at 80°C for 4 hours.

EFFECT: invention increases strength of glued vulcanised rubber.

2 tbl, 2 ex

Description

The invention relates to a method for attaching vulcanized rubbers to each other and can be used in the rubber industry.

A known method of bonding and sealing rubbers by applying nitrogen-containing monoacrylates to the bonded surfaces of the adhesive material with the addition of a polymerization initiator followed by contacting the surfaces under anaerobic conditions, the product of condensation of esters of acrylic acids and mono-, di- or trialkanolamines is used as nitrogen-containing monoacrylates (USSR Copyright Certificate No. 378401, class C09J 5/00; publ. 18.04.73).

However, this method, although it provides high strength when bonding rubber products, is intended for bonding products under anaerobic conditions, which complicates the technology.

A known method of bonding various materials with adhesives based on epoxy resins with hardeners using radiation treatment of the cured adhesive, which are additionally introduced plasticizer. (USSR author's certificate No. 2148593, class C69J 5/00; publ. 10.05.00).

However, this method requires subjecting the parts to be glued to radiation in moderate doses, which complicates the bonding process.

There is a method of bonding and sealing rubbers by applying an adhesive material — oligoester acrylates — to the bonded surfaces with the addition of a polymerization initiator followed by contacting the surfaces under anaerobic conditions (USSR Author's Certificate No. 378402, class C09J 5/00; Publ. 18.04.73).

However, this method, although it provides high strength when bonding rubber products, is intended for bonding products under anaerobic conditions, which complicates bonding.

The closest is the method of fixing the rubbers to each other, which consists in applying glue based on polychloroprene rubber to the bonded surfaces of the rubbers, followed by contacting the surfaces. Use nairit NT or nairit DP in combination with butylphenol formaldehyde resin in 88NT or 88CA adhesive. Before applying to the glue, 1-3 wt.h. modifier - methylphosphite borate - per 100 parts by weight glue. Then carry out the drying of the adhesive film at room temperature for 1-2 minutes and contacting the bonded surfaces is carried out under load for 24 hours (Patent No. 2401289, class C09J 5/00; Publ. 10.10.10).

However, this method does not provide a sufficiently high strength when bonding products from vulcanized rubber to each other.

Objective: to develop a method of attaching rubbers to each other, providing increased strength when bonding vulcanized rubber to each other.

The technical result is to increase the strength when bonding vulcanized rubber to each other.

The stated technical result is achieved by the fact that in the method of fixing the vulcanized rubbers to each other, glue based on polychloroprene rubber Nairit NT or Nairit DP in combination with butylphenol-formaldehyde resin and a modifier added to the adhesive 88HT or 88CA before applying it to the surface with subsequent drying of the adhesive film at room temperature for 1-2 minutes and contacting the surfaces under the load for 24 hours, and modifiers are used as a modifier itsirovannoe carbon fibers of 2-3 mm in size in an amount of 0.1-0.5 parts by weight per 100 parts by weight glue obtained by pyrolysis at 400 ° C for 30 min of polyvinyl alcohol fibers treated with methyl phosphite borate, followed by treatment at 80 ° C for 4 hours of the obtained carbon fiber with a mixture of methyl phosphite borate and triethanolamine in a weight ratio of 1: 2.

Adhesive 88NT (TU2252-033-45539771-2000) which includes (parts by weight): polychloroprene rubber Nairit NT - 100, butylphenol formaldehyde resin 101K - 90, zinc oxide - 5, magnesium oxide - 12, thiuram - 2, organic the solvent is 800. As a solvent, a mixture of nephras and ethyl acetate in a ratio of 1: 1 is used.

Glue 88CA (TU 381051760-89), which includes (parts by weight):

polychloroprene rubber Nairit DP - 90, butylphenol formaldehyde resin 101K - 90, zinc oxide - 5, magnesium oxide - 11, water - 3 and an organic solvent - 800. A mixture of nephras and ethyl acetate in a 1: 1 ratio is used as an organic solvent.

Polychloroprene rubbers Nairit NT with a high crystallization rate (TU-601781-73), Nairit DP with an average crystallization rate (TU-6-01-1319-85), are the main film-forming in adhesive adhesives.

Butylphenol formaldehyde resin 101K (TU-60004691277193-97).

Vulcanizing group: zinc oxide (zinc white GOST 202-84), magnesium oxide (burnt magnesia GOST 844-79) were previously used in adhesive compositions (Kardashov D.A., Petrova A.V. Polymer adhesives. M: Chemistry, 1983 )

Organic solvent: a mixture of ethyl acetate (GOST 8981-78) and nefras (TU 3840167109-92).

Carbon fiber 2-3 mm in size, obtained on the basis of polyvinyl alcohol fibers pretreated with methyl phosphite borate, by pyrolysis at 400 ° C for 30 minutes.

Methylphosphite borate is a viscous, unpainted liquid, readily soluble in water, dimethylformamide, acetone, alcohols (US Pat. No. 2190697). Widely known as a combustion inhibitor.

Triethanolamine (TU 2423-061-05807977-2002) is used for gas purification in the production of pure carbon dioxide, in the textile and cement industries, in the production of cutting fluids, cosmetics, household chemical goods, as raw materials in organic synthesis.

To modify carbon fibers, a mixture is preliminarily prepared by mixing methylphosphite borate and triethanolamine in a mass ratio of 1: 2 at room temperature, which is a transparent, viscous mass of light yellow color.

The carbon fiber was modified by treating it with a mixture of methylphosphite borate and triethanolamine in a mass ratio of 1: 2 at 80 ° for four hours.

When using modified carbon fiber in the adhesive composition, the adhesive properties of the adhesive composition are significantly increased. As a result of the modification of the fibers, functional groups are contained on their surface that can interact with the macromolecule of the film-forming polymer. In addition, an increase in the adhesion strength of glue with rubber occurs due to the effect of "mechanical jamming" of carbon fibers in an array of bonded vulcanized rubbers. In addition, there is an increase in the cohesive strength of the adhesive film.

This explains the increase in strength when bonding vulcanized rubber to each other.

The method of attaching rubbers to each other is as follows.

Before applying to the polychloroprene rubber glue, before application to the bonded surfaces, the calculated amount of modified carbon fibers is introduced and the contents are mixed for 5-10 minutes until a homogeneous mass is obtained. This method was used to fasten vulcanized rubbers based on polyisoprene rubber (SKI-3), ethylene propylene rubber (SKEPT-40), nitrile butadiene rubber (SKN-18M) and chloroprene rubber (Neoprene AC) to each other. The prepared glue was applied once to the prepared surface, the adhesive film was dried at room temperature (20 ° C) for 1-2 minutes, after which the glued surfaces were pressed tightly and kept under load for 2 kg for 24 hours.

Shear adhesion was determined on an MPC-250 tensile testing machine (RTM 1.2.126-88). The various contents of the modified indicated fibers in adhesives of 88HT and 88CA grades were investigated (Tables 1, 2).

The method is illustrated by the following example.

Example 1. In the adhesive brand 88HT before applying to the bonded surface, enter the calculated amount of modified these fibers and mix the contents of 5-10 minutes until a homogeneous mass. This method was used to attach vulcanized rubbers based on SKEPT-40 and Neoprene AC to each other. The prepared glue was applied once to the prepared surface, the adhesive film was dried at room temperature (20 ° C) for 1-2 minutes, after which the glued surfaces were pressed tightly and kept under load for 2 kg for 24 hours. After that, the shear strength was determined (Table 1).

Example 2. Obtain adhesive compounds as described in example 1, but as an adhesive use adhesive brand 88CA. Vulcanized rubbers based on SKI-3, SKN-18M and Neoprene AS are used as a substrate (Table 2).

As can be seen from table 1.2, the proposed method of attaching vulcanized rubbers to each other provides high strength properties of adhesive joints. Thus, the shear strength of the adhesive joint when gluing vulcanized rubber based on Neoprene AC with 88CA brand adhesive according to the prototype is 1.22 MPa, and using the proposed modifier 1.96 MPa.

We found that the reason for the increase in the adhesive performance of adhesive compositions is an increase in the cohesive strength of the adhesive film when modified carbon fibers are introduced into the composition, as well as their partial penetration into the surface layers of rubbers.

Table 1 Substrate Type Shear Strength, MPa The content of the modifier, parts by weight per 100 parts by weight glue Prototype 0.1 0.3 0.5 SKEPT-40 1.30 1.35 1.24 1.27 Neoprene speaker 1.80. 1,57 1.72 0.98

table 2 Substrate Type Shear Strength, MPa The content of the modifier, parts by weight per 100 parts by weight glue Prototype 0.1 0.3 0.5 SKI-3 1.23 1.33 1.31 1.30 SKN-18M 0.71 0.65 0.74 - Neoprene speaker 1.89 1.75 1.96 1.22

The technical and economic effect obtained from the use of the adhesive composition lies in the fact that its use can significantly improve the quality of fixing products from vulcanized rubber to each other.

Claims (1)

A method of attaching vulcanized rubbers to each other by applying Nairit NT or Nairit DP in combination with butylphenol-formaldehyde resin and a modifier added to 88NT or 88CA adhesive before applying it to the surface, followed by drying of the adhesive film at room temperature for 1-2 minutes and contacting the surfaces under the load for 24 hours, characterized in that a modified carbon fiber of size 2-3 is used as a modifier mm in an amount of 0.1-0.5 parts by weight per 100 parts by weight glue obtained by pyrolysis at 400 ° C for 30 min of polyvinyl alcohol fibers treated with methyl phosphite borate, followed by treatment at 80 ° C for 4 hours of the obtained carbon fiber with a mixture of methyl phosphite borate and triethanolamine in a weight ratio of 1: 2.