RU2401289C2 - Method of gluing rubber to each other - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: polychloroprene rubber-based glue is applied onto rubber surfaces and said surfaces are brought into contact. Nairite NT or nairite DP combined with 88NT or 88SA butylphenol formaldehyde resin is used. Before application, methylphosphite borate modifier is added to the glue in amount of 1-3 pts. wt per 100 pts. wt of glue. The glue film is then dried at room temperature for 1-2 minutes and the glued surfaces are brought into contact under a load for 24 hours.

EFFECT: high strength of the glue joint when gluing vulcanised rubber and simplification of the gluing process.

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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, published on April 18, 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 compounds, which are additionally introduced plasticizer. (USSR author's certificate No. 2148593, class C09J 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 oligoester acrylates with the addition of a polymerization initiator followed by contacting the surfaces under anaerobic conditions on the bonded surfaces of the adhesive material (USSR Author's Certificate No. 378402, class C09J 5/00, published on April 18, 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 rubbers to each other and to metals by applying polymerizable monomers to the surfaces to be bonded and then contacting the surfaces to be bonded, 2-methyl-4-halohexatrienes-1,3,5 are used as the polymerizable monomer, alone or with the addition of a radical initiator type, or with their own polymers or polychloroprene dissolved in them (USSR Author's Certificate No. 426490, class C09J 5/00, publ. 15.09.75).

However, this method, although it provides a sufficiently high strength when bonding products made of vulcanized rubber, requires additional heating of the samples at high temperature.

Objective: to develop a method of attaching rubbers to each other, providing increased strength and fire resistance of the adhesive joint at the rubber-adhesive border.

The technical result is to provide increased strength of the adhesive joint when attaching vulcanized rubbers to each other, simplifying the bonding technology.

The technical result achieved is achieved by the fact that by the method of fixing vulcanized rubbers based on various rubbers to each other by applying glue based on polychloroprene rubber to the glued surfaces and then contacting the surfaces, moreover, Nairit NT or Nairit DP in combination with butylphenol formaldehyde are used as the basis for the polychloroprene adhesive resin in the adhesive brand 88NT or 88CA, before applying to the surface in the glue, an additional modifier is added - methyl phosphite borate - in an amount of 1.0- 3.0 parts by weight per 100 parts by weight glue, and after applying the glue, the glue film is dried at room temperature for 1-2 minutes, and the bonded surfaces are contacted under load for 24 hours.

Adhesive 88NT (TU 2252-033-45539771-2000), which includes (parts by weight): polychloroprene rubber Nairit NT 100, butylphenol formaldehyde resin 101K 90, zinc oxide 5, magnesium oxide 12, thiuram 2, organic solvent 800. As a solvent, a mixture of nephras and ethyl acetate in a ratio of 1: 1.

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. As an organic solvent, use a mixture of nefras and ethyl acetate in a ratio of 1: 1.

Polychloroprene rubbers, Nairit NT (TU-601781-73), Nairit DP (TU-6-01-131919-85), are the main film-forming in adhesive adhesives.

Butylphenol formaldehyde resin 101 K (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).

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

As a result of the interaction of the modifier with the macromolecule of polychloroprene rubber, an increase in the concentration of polar groups and the formation of additional chemical bonds during the interaction of this modifier with mobile allylic chlorine atoms in the macromolecules of chloroprene rubber, which increases the strength at the rubber-adhesive interface when bonding vulcanized rubber to each other.

The declared limits of the quantities of the introduced modifier are due to the fact that with a decrease or increase in the indicated dosages, the adhesive strength during gluing decreases.

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

The calculated amount of modifier is introduced into the adhesive based on polychloroprene rubber before application to the surfaces to be glued 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-18) and chloroprene rubber (Neoprene) to each other. One-time application of the prepared adhesive on the prepared surface, drying of the adhesive film 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 using an MPC-250 tensile testing machine (RTM 1.2.126-88). The fire resistance of the adhesive composition was determined by the method of determining resistance to burning (GOST 28157-89), by preliminary casting it on a flat glass surface and subsequent drying at room temperature for one day to a constant weight.

Various modifier contents in adhesives of 88HT and 88CA grades were studied (Tables 1 and 2).

The method is illustrated by the following example.

Example 1. The calculated amount of modifier is introduced into 88NT adhesive prior to application onto the surfaces to be glued and the contents are mixed for 5-10 minutes until a homogeneous mass is obtained. This method was used for fixing vulcanized rubbers based on SKI-3, SKEPT-40, SKN-18 and Neoprene to each other. One-time application of the prepared adhesive on the prepared surface, drying of the adhesive film 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, shear strength was determined.

Example 2. Obtain adhesive compounds, as described in example 1, but as the adhesive used adhesive brand 88CA.

As can be seen from tables 1 and 2, the proposed method of attaching vulcanized rubbers to each other provides high strength properties of adhesive joints. So the strength of the adhesive joint under shear when bonding vulcanized rubber based on SKN-18 with 88NT adhesive according to the prototype is 0.46 MPa, and using the proposed modifier 1.39 MPa.

Table 1 Substrate Type Shear Strength, MPa Methyl Phosphite Borate Prototype
glue 88НТ The content of the modifier, parts by weight per 100 parts by weight glue 1,0 2.0 3.0 SKI-3 0.69 0.94 1.13 0.61 SKEPT-40 1,08 1.27 1.23 0.99 SKN-18 0.89 1.01 1.39 0.46 Neoprene 0.80 0.98 0.92 0.73 Fire resistance - s / fade out s / fade out s / fade out burns

table 2 Substrate Type Shear Strength, MPa Methyl Phosphite Borate Prototype
adhesive 88CA The content of the modifier, parts by weight per 100 parts by weight glue 1,0 2.0 3.0 SKI-3 1,08 1,04 1.30 1,02 SKEPT-40 1D2 1.29 1.17 0.70 Neoprene 1.10 1.18 1.22 1.00 Fire resistance of the adhesive composition - s / fade out s / fade out s / fade out burns

We found that the reason for the increase in adhesive performance with this method of attachment is not only an increase in the concentration of polar groups when a modifier is introduced into the adhesive, but also the formation of additional chemical bonds during the interaction of this modifier with mobile allylic chlorine atoms in the polychloroprene rubber macromolecules, which leads to an increase mobility of the macromolecule and deeper diffusion of its sections deep into the surface of the vulcanizate.

The technical and economic effect obtained from the application of the fastening method lies in the fact that its application can significantly improve the quality of fastening of products from vulcanized rubber.

based on various rubbers, simplify the bonding process.

Claims (1)

A method of attaching vulcanized rubbers based on various rubbers to each other by applying glue based on polychloroprene rubber to the glued surfaces and then contacting the surfaces, characterized in that the base of the polychloroprene adhesive is Nairit NT or Nairit DP in combination with butylphenol-formaldehyde resin in 88NT adhesive or 88CA, before applying to the surface, an additional modifier is added to the adhesive — methylphosphite borate — in an amount of 1-3 parts by weight. per 100 parts by weight glue and after applying the glue, the glue film is dried at room temperature for 1-2 minutes, and the bonded surfaces are contacted under load for 24 hours.