CA1117856A - Method of bonding - Google Patents
Method of bondingInfo
- Publication number
- CA1117856A CA1117856A CA000309139A CA309139A CA1117856A CA 1117856 A CA1117856 A CA 1117856A CA 000309139 A CA000309139 A CA 000309139A CA 309139 A CA309139 A CA 309139A CA 1117856 A CA1117856 A CA 1117856A
- Authority
- CA
- Canada
- Prior art keywords
- adhesive composition
- nitromethane
- adhesive
- weight
- polymethyl methacrylate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/12—Bonding of a preformed macromolecular material to the same or other solid material such as metal, glass, leather, e.g. using adhesives
- C08J5/122—Bonding of a preformed macromolecular material to the same or other solid material such as metal, glass, leather, e.g. using adhesives using low molecular chemically inert solvents, swelling or softening agents
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/12—Bonding of a preformed macromolecular material to the same or other solid material such as metal, glass, leather, e.g. using adhesives
- C08J5/124—Bonding of a preformed macromolecular material to the same or other solid material such as metal, glass, leather, e.g. using adhesives using adhesives based on a macromolecular component
- C08J5/125—Adhesives in organic diluents
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
- C09J133/04—Homopolymers or copolymers of esters
- C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
- C09J133/10—Homopolymers or copolymers of methacrylic acid esters
- C09J133/12—Homopolymers or copolymers of methyl methacrylate
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2333/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
- C08J2333/04—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters
- C08J2333/06—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters of esters containing only carbon, hydrogen, and oxygen, the oxygen atom being present only as part of the carboxyl radical
- C08J2333/10—Homopolymers or copolymers of methacrylic acid esters
- C08J2333/12—Homopolymers or copolymers of methyl methacrylate
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
- C08L2666/28—Non-macromolecular organic substances
- C08L2666/36—Nitrogen-containing compounds
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Medicinal Chemistry (AREA)
- Materials Engineering (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacturing & Machinery (AREA)
- Polymers & Plastics (AREA)
- Engineering & Computer Science (AREA)
- Adhesives Or Adhesive Processes (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Treatments Of Macromolecular Shaped Articles (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method of bonding a surface of an article made from a polymethyl methacrylate resin to another surface, which comprises treating at least one of the said surfaces with an adhesive composition comprising nitromethane and/or nitroethane, contacting the said surfaces and drying the said surfaces to form a bond between the said surfaces. The second surface is preferably a surface of a polymethyl methacrylate resin article but may be of any other material as desired.
The use of nitromethane and/or nitroethane in the adhesive composition has been found to improve the adhesive bond compared with the use of other solvents as adhesives.
A method of bonding a surface of an article made from a polymethyl methacrylate resin to another surface, which comprises treating at least one of the said surfaces with an adhesive composition comprising nitromethane and/or nitroethane, contacting the said surfaces and drying the said surfaces to form a bond between the said surfaces. The second surface is preferably a surface of a polymethyl methacrylate resin article but may be of any other material as desired.
The use of nitromethane and/or nitroethane in the adhesive composition has been found to improve the adhesive bond compared with the use of other solvents as adhesives.
Description
The present invention relates to a method of bonding polymethyl methacrylate resins.
In order to bond methacrylate ester resins to one another or to other resins, volatile organic solvents which can dissolve these resins may be used as adhesives.
The solvents swell or dissolve the boundary layers of the resin articles to be bonded together and give a visually essentially homogeneous bond under favourable conditions after evaporation.
There are many organic solvents for polymethacrylates, but only a few of them can be used as adhesives.
Desirably the solvent is intended quickly to dissolve the resin faces to be bonded together, rapidly to provide sufficient stability under load in order to exclude the inadvertent displacement of the bonded parts and to harden into a visually clear and bubble-free bond having tensile strength. Most organic solvents fulfil only some of these requirements.
Most solvents rapidly generate a high swelling pressure in the region near the surface. This high pressure, especially in the case of highly stressed, for example3 curved parts, causes so-called stress cracking which originates at right angles to the adhesive face. Only a few solvents, e.g. some aliphatic-chlorinated hydrocarbons, produce no stress cracking.
However, most of these solvents evaporate so quickly in the air that as a result of the drop in temperature due to evaporation of the solvent, atmospheric moisture is precipitated in the adhesive joint and causes permanent clouding~ Air bubbles also often arise as a result of ,, the shrinkage of the swollen plastic surface during gradual evaporation of the solvent.
In all cases, the tensile strength of the adhesive joint is lower than that of the bonded resins themselves, so that the adhesive joint ruptures under loading.
In view of these various factors, methylene chloride (dichloromethane) has proved hitherto to be the adhesive best suited to methacrylic ester resins. It dissolves the resin quickly and results within 10 seconds in a bond stable under load, so that frequently even desired corrections of the relative position of the bonded resin articles are no longer possible. After 2 days the final strength of the bond is reached, but the margin of the adhesive face may be slightly cloudy, which can generally be avoided only if the operation is carried out in an atmosphere having low absolute atmospheric moisture.
It is an object of the invention to provide a method of bonding polymethyl methacrylate resins using materials having advantageous adhesive properties.
According to the present inven~ion we provide a method of bonding a surface of an article made of a polymethyl methacrylate resin to another surface which comprises treating at least one of said surfaces with an adhesive composition comprising at least one nitroalkane selected from nitromethane and nitroethane, contacting the said surfaces and drying the said surfaces to form a bond between the said surfaces.
From experiments which we have carried out in accordance with the present invention, we have found ~ 4 -that the use of nitromethane or nitroethane tends to obviate the disadvantages observed with previous solvents, the resulting bonds being free of clouding and bubbles and having increased tensile strength.
The method according to the present invention may be employed for example either to bond together two articles both made from a polymethyl methacrylate resin or to bond one such article to an article made from another material.
In the method according to the present invention, the adhesive composition is advantageously applied to the article made from a polymethy~ methacrylate resin in the case when the second-mentioned article is made from a different material.
The term "polymethyl methacrylate resin'~ is used herein to denote not only homopolymersof methyl methacrylate but also copolymers containing a predominant proportion, especially more than 80% by weight, of units of methyl methacrylate and a smaller portion of one or more unsaturated comonomers copolymerisable therewith, such as other methacryla~e esters, esters of acrylic acid, styrene, acrylo- or methacrylonitrile, vinyI
chloride, vinylidene chloride or vinyl esters. The resin to be bonded should be soluble or at least strongly swellable in suitable organic solvents, i.e. they should be substantially non-cross-linked. The molecular weight of the resin is only of minor importance for a good - bonding effect. Consequently, non-meltable bul~
polymers can be bonded just as well as extruded or injection-moulded resins. The bonding of injection mouldings is one of the special advantages of the use of L7~5~i nitromethane or nitroethane as adhesives according to the invention.
Nitroethane acts on polymethyl methacrylate resins rather more slowly than nitromethane. Thus, the period during which the relative position of the articles to be bonded can be corrected after joining is thereby ` extended. Due to its higher boiling point nitroethane evaporates more slowly than nitromethane, so that the drop in temperature due to evaporation is reduced and the risk that the adhesive joint will be clouded by condensation water in the case of high atmospheric moisture is reduced still further. This is especially true in the case where nitroethane is used in admixture wi-th other solvents such as methylene chloride as adhesive or adhesive additive. Nitroethane can be employed for all the applications described in any desired mixture ratio with nitromethane. The above-mentioned differences regarding the speed of action and of evaporation are then manifested in proportion to the mixture ratio Although nitromethane or nitroethane can each be used alone as adhesive, it is preferred to use mixtures of nitromethane and/or nitroethane with other volatile organic liquids with boiling points of not more than 200, preferably below 150. These other liquids can themselves be solvents for the resins to be bonded and include for example ketones, esters, ethers and aliphatic chlorinated hydrocarbons, e.g. acetone, cyclohexanone, methyl acetate, butyl acetate, tetrahydro-furan, chloroform, carbon tetrachloride, dichloromethane, dichloroethane, etc. These solvents ~ se have the .
above-described disadvantages as adhesives, but in admixture with at least 30% by weight of nitromethane or nitroethane (calculated on the weight of the mixture) these disadvantages are considera~ly reduced. Thus, stress cracking clearly decreases and adhesive strength is increased. The following table sets out the adhesive tensile strength of bonded articles of extruded polymethyl methacrylate resin 14 days after bonding:-Solvent Adhesive Mixture with Adhesive tensile nitromethane, tensile strength weight ratio strength N/mm2 of solvent to N/mm2 nitromethane . _ . . _ . .
Acetone 23.9 40 : 60 34O0 Cyclo- 1605 20 : 80 35.2 hexanone Toluene 19.8 40 : 60 32.4 Tetra- 22.8 60 : 40 33.3 hydro-furan Dichloro- 35O9 60 : 40 42.4 methane (methylene chloride) 1,2-di- 34.2 60 : 40 36.4 chloro-ethane . . .
Under the same conditions nitromethane alone provides an adhesive tensile strength of 36.6 N/mm . The chlorinated hydrocar~ons which alone give similarly high strengths ena~le, in a mixture with nitromethane or 7B.~
nitroethane, higher strength values to be achieved than with each of the components alone. Mixtures of nitro-methane or nitroethane and dichloromethane in a weight ratio between 30:70 to 80:20 are preferably used in the method accorcling to the invention.
Nitromethane or nitroethane can also be used in admixture with organic liquids which are not solvents for the resins to be bonded and which do not develop their own adhesive effect. They can be selected in order to extend the swelling time of the adhesive composition or to prolong the period after which stability under load is reached, which is sometimes desirable in the case of difficult bonds. These additives can be less volatile than nitromethane or nitroethane, in which case the lower speed of evaporation prevents the formation of bubbles in the adhesive joint and clouding due to condensation of atmospheric moisture.
Examples of such mixtures and the strengths obtained in the bonding of polymethyl methacrylate resin are given in the following table:
Solvent Additi~e Weight Adhesive ratio (solvent strengt~
- - - -to additive) in N/mm Nitromethane Ethanol 80:20 31.5 Nitromethane Trichlorethane 60:40 27.8 Nitromethane Dimethylformamide 70:30 31.3 Nitromethane + Phenoxyethanol 95: 5 43.0 dichloromethane (40:55 parts by weight) ~ ~ 7 When nitromethane or nitroethane or a mixture thereof with volatile organic liquids are used as adhesive, the adhesive bond is formed of the material of the resin to be bonded. It is, however, also possible to use in the adhesive composition so-called adhesive lacquers which contain a dissolved polymer in the solvent. After the solvent has evaporated, the polymer forms the adhesive bond. Such polymer additives include e.g. polymethyl methacrylate, polyvinyl acetate, polyvinyl ether or cellulose acetobutyrate. In practice, an upper limit is set on the proportion of polymer by the viscosityof the solution. The solution viscosity at 20 should generally not lie above 10,000 mPa.s.
Advantageously, solutions containing approximately 3 to 30% by weight of a poly~er are employed, such ` polymer concentrations providing viscosities in the region of 500 to 2,000 mPa.s for the solution, The method according to the invention is of particular application for bonding two articles each made of a polymethyl methacrylate resin. In order to bond a polymethyl methacrylate article to an article made of another material such as wood, paper, cardboard, leather, metal, ceramic material, glass, porcelain or resins of other kinds, e.gO phenol resin or aminoplast resin moùldings, polycarbonate, PVC, urethane foam materials and the like, adhesive lacquers are advanta-geously used, if nitromethane or nitroethane alone or mixtures thereof with volatile organic liquids, cannot give the desired adhesive strengthO
The bonding of extruded polymethacrylate resin 11~7~
g articles to one another is a preferred area of application of the method of the invention. Cast -polymethyl methacrylate articles can similarly be bonded together. Such articles are preferably prepared from homopolymers of methyl methacrylate or copolymers of rnethyl methacrylate with at most 10% by weight of other unsaturated monomers. The use of nitromethane or nitroethane in a mixture with dichloromethane is preferred for this purpose.
The second table set out above refers to the use of a mixture consisting of 40 parts by weight of nitromethane and 55 parts by weight of dichloromethane to which 5 parts by weight of phenoxyethanol have been added. The use of such a combination of ingredients with the optional substitution of nitroethane and/or the optional variation of the relative amounts of the ingredients is advantageous since, when it is applied, clear adhesive joints are obtained even when working in an atmosphere with a high relative humidity. The same effect can be achieved i;f phenoxyethanol is replaced by other glycol ethers such as methyl glycol or alkyldiglycol ether. To obtain a high adhesive strength, these additives should be employed in quantities up to 10% by weight relative to the total solvent mixture.
The following Examples which illustrate the invention describe a bonding operation using nitromethane and another bonding operation using nitroethane under otherwise identical conditions. The strength result with nitromethane is given first, followed by the value obtained with nitroethane.
~1~L7~35~
E~
The longitudinal sides of two test-pieces (10 mm x 270 mm x 60 mm) of polymethyl methacrylate are dipped for approximately 60 seconds in nitromethane or nitro-ethane and joined together. Within 120 seconds the bondis stable under load, i.e. it is no longer displaceable.
By the loading of a joining part with a weight of 150 g/cm the adhesive faces are brought into intimate contact~ The load is maintained for 24 hours, After storage at room temperature for 13 days without loading 10 test-pieces (8 mm x 20 mm x 120 mm) are produced from the bonded article and the tensile strength is determined by reference to DIN 53455. Result: 36~6 N/mm and 34~8 N/mm respectively.
Example 2 The bonding operation described in Example l is carried out except that a mixture of methylene chloride and either nitromethane or nitroethane (60/40) is used as solvent adhesive. The test-piece is stable under load within 20 seconds. The tensile strength after storage for 14 days is 43.7 N/mm and 36.4 N/mm respectively.
Example 3 The bonding operation described in Example 1 is carried out except that a solvent mixture of n~ethylene chloride/nitromethane or nitroethane/phenoxyethanol (55/40/5) is used for the operation. The adhesive joint is completely clear and free of bubbles. After storage for 14 days at room temperature a strength of 43 N/mm2 and 33.7 N/mm2 respectively is achieved.
Ex~e~
S The test is conducted as described in Example 1 except that the solution applied is one of 30 parts of polymethyl methacrylate in 70 parts of a solvent mixture consisting of methylene chloride/nitromethane or nitroethane/phenoxyethanol (57/40/3). The bond is stable under load after 3 minutes. After storage for 14 days a strength of 37 N/mm and 31.8 N/mm respectively is obtained.
In order to bond methacrylate ester resins to one another or to other resins, volatile organic solvents which can dissolve these resins may be used as adhesives.
The solvents swell or dissolve the boundary layers of the resin articles to be bonded together and give a visually essentially homogeneous bond under favourable conditions after evaporation.
There are many organic solvents for polymethacrylates, but only a few of them can be used as adhesives.
Desirably the solvent is intended quickly to dissolve the resin faces to be bonded together, rapidly to provide sufficient stability under load in order to exclude the inadvertent displacement of the bonded parts and to harden into a visually clear and bubble-free bond having tensile strength. Most organic solvents fulfil only some of these requirements.
Most solvents rapidly generate a high swelling pressure in the region near the surface. This high pressure, especially in the case of highly stressed, for example3 curved parts, causes so-called stress cracking which originates at right angles to the adhesive face. Only a few solvents, e.g. some aliphatic-chlorinated hydrocarbons, produce no stress cracking.
However, most of these solvents evaporate so quickly in the air that as a result of the drop in temperature due to evaporation of the solvent, atmospheric moisture is precipitated in the adhesive joint and causes permanent clouding~ Air bubbles also often arise as a result of ,, the shrinkage of the swollen plastic surface during gradual evaporation of the solvent.
In all cases, the tensile strength of the adhesive joint is lower than that of the bonded resins themselves, so that the adhesive joint ruptures under loading.
In view of these various factors, methylene chloride (dichloromethane) has proved hitherto to be the adhesive best suited to methacrylic ester resins. It dissolves the resin quickly and results within 10 seconds in a bond stable under load, so that frequently even desired corrections of the relative position of the bonded resin articles are no longer possible. After 2 days the final strength of the bond is reached, but the margin of the adhesive face may be slightly cloudy, which can generally be avoided only if the operation is carried out in an atmosphere having low absolute atmospheric moisture.
It is an object of the invention to provide a method of bonding polymethyl methacrylate resins using materials having advantageous adhesive properties.
According to the present inven~ion we provide a method of bonding a surface of an article made of a polymethyl methacrylate resin to another surface which comprises treating at least one of said surfaces with an adhesive composition comprising at least one nitroalkane selected from nitromethane and nitroethane, contacting the said surfaces and drying the said surfaces to form a bond between the said surfaces.
From experiments which we have carried out in accordance with the present invention, we have found ~ 4 -that the use of nitromethane or nitroethane tends to obviate the disadvantages observed with previous solvents, the resulting bonds being free of clouding and bubbles and having increased tensile strength.
The method according to the present invention may be employed for example either to bond together two articles both made from a polymethyl methacrylate resin or to bond one such article to an article made from another material.
In the method according to the present invention, the adhesive composition is advantageously applied to the article made from a polymethy~ methacrylate resin in the case when the second-mentioned article is made from a different material.
The term "polymethyl methacrylate resin'~ is used herein to denote not only homopolymersof methyl methacrylate but also copolymers containing a predominant proportion, especially more than 80% by weight, of units of methyl methacrylate and a smaller portion of one or more unsaturated comonomers copolymerisable therewith, such as other methacryla~e esters, esters of acrylic acid, styrene, acrylo- or methacrylonitrile, vinyI
chloride, vinylidene chloride or vinyl esters. The resin to be bonded should be soluble or at least strongly swellable in suitable organic solvents, i.e. they should be substantially non-cross-linked. The molecular weight of the resin is only of minor importance for a good - bonding effect. Consequently, non-meltable bul~
polymers can be bonded just as well as extruded or injection-moulded resins. The bonding of injection mouldings is one of the special advantages of the use of L7~5~i nitromethane or nitroethane as adhesives according to the invention.
Nitroethane acts on polymethyl methacrylate resins rather more slowly than nitromethane. Thus, the period during which the relative position of the articles to be bonded can be corrected after joining is thereby ` extended. Due to its higher boiling point nitroethane evaporates more slowly than nitromethane, so that the drop in temperature due to evaporation is reduced and the risk that the adhesive joint will be clouded by condensation water in the case of high atmospheric moisture is reduced still further. This is especially true in the case where nitroethane is used in admixture wi-th other solvents such as methylene chloride as adhesive or adhesive additive. Nitroethane can be employed for all the applications described in any desired mixture ratio with nitromethane. The above-mentioned differences regarding the speed of action and of evaporation are then manifested in proportion to the mixture ratio Although nitromethane or nitroethane can each be used alone as adhesive, it is preferred to use mixtures of nitromethane and/or nitroethane with other volatile organic liquids with boiling points of not more than 200, preferably below 150. These other liquids can themselves be solvents for the resins to be bonded and include for example ketones, esters, ethers and aliphatic chlorinated hydrocarbons, e.g. acetone, cyclohexanone, methyl acetate, butyl acetate, tetrahydro-furan, chloroform, carbon tetrachloride, dichloromethane, dichloroethane, etc. These solvents ~ se have the .
above-described disadvantages as adhesives, but in admixture with at least 30% by weight of nitromethane or nitroethane (calculated on the weight of the mixture) these disadvantages are considera~ly reduced. Thus, stress cracking clearly decreases and adhesive strength is increased. The following table sets out the adhesive tensile strength of bonded articles of extruded polymethyl methacrylate resin 14 days after bonding:-Solvent Adhesive Mixture with Adhesive tensile nitromethane, tensile strength weight ratio strength N/mm2 of solvent to N/mm2 nitromethane . _ . . _ . .
Acetone 23.9 40 : 60 34O0 Cyclo- 1605 20 : 80 35.2 hexanone Toluene 19.8 40 : 60 32.4 Tetra- 22.8 60 : 40 33.3 hydro-furan Dichloro- 35O9 60 : 40 42.4 methane (methylene chloride) 1,2-di- 34.2 60 : 40 36.4 chloro-ethane . . .
Under the same conditions nitromethane alone provides an adhesive tensile strength of 36.6 N/mm . The chlorinated hydrocar~ons which alone give similarly high strengths ena~le, in a mixture with nitromethane or 7B.~
nitroethane, higher strength values to be achieved than with each of the components alone. Mixtures of nitro-methane or nitroethane and dichloromethane in a weight ratio between 30:70 to 80:20 are preferably used in the method accorcling to the invention.
Nitromethane or nitroethane can also be used in admixture with organic liquids which are not solvents for the resins to be bonded and which do not develop their own adhesive effect. They can be selected in order to extend the swelling time of the adhesive composition or to prolong the period after which stability under load is reached, which is sometimes desirable in the case of difficult bonds. These additives can be less volatile than nitromethane or nitroethane, in which case the lower speed of evaporation prevents the formation of bubbles in the adhesive joint and clouding due to condensation of atmospheric moisture.
Examples of such mixtures and the strengths obtained in the bonding of polymethyl methacrylate resin are given in the following table:
Solvent Additi~e Weight Adhesive ratio (solvent strengt~
- - - -to additive) in N/mm Nitromethane Ethanol 80:20 31.5 Nitromethane Trichlorethane 60:40 27.8 Nitromethane Dimethylformamide 70:30 31.3 Nitromethane + Phenoxyethanol 95: 5 43.0 dichloromethane (40:55 parts by weight) ~ ~ 7 When nitromethane or nitroethane or a mixture thereof with volatile organic liquids are used as adhesive, the adhesive bond is formed of the material of the resin to be bonded. It is, however, also possible to use in the adhesive composition so-called adhesive lacquers which contain a dissolved polymer in the solvent. After the solvent has evaporated, the polymer forms the adhesive bond. Such polymer additives include e.g. polymethyl methacrylate, polyvinyl acetate, polyvinyl ether or cellulose acetobutyrate. In practice, an upper limit is set on the proportion of polymer by the viscosityof the solution. The solution viscosity at 20 should generally not lie above 10,000 mPa.s.
Advantageously, solutions containing approximately 3 to 30% by weight of a poly~er are employed, such ` polymer concentrations providing viscosities in the region of 500 to 2,000 mPa.s for the solution, The method according to the invention is of particular application for bonding two articles each made of a polymethyl methacrylate resin. In order to bond a polymethyl methacrylate article to an article made of another material such as wood, paper, cardboard, leather, metal, ceramic material, glass, porcelain or resins of other kinds, e.gO phenol resin or aminoplast resin moùldings, polycarbonate, PVC, urethane foam materials and the like, adhesive lacquers are advanta-geously used, if nitromethane or nitroethane alone or mixtures thereof with volatile organic liquids, cannot give the desired adhesive strengthO
The bonding of extruded polymethacrylate resin 11~7~
g articles to one another is a preferred area of application of the method of the invention. Cast -polymethyl methacrylate articles can similarly be bonded together. Such articles are preferably prepared from homopolymers of methyl methacrylate or copolymers of rnethyl methacrylate with at most 10% by weight of other unsaturated monomers. The use of nitromethane or nitroethane in a mixture with dichloromethane is preferred for this purpose.
The second table set out above refers to the use of a mixture consisting of 40 parts by weight of nitromethane and 55 parts by weight of dichloromethane to which 5 parts by weight of phenoxyethanol have been added. The use of such a combination of ingredients with the optional substitution of nitroethane and/or the optional variation of the relative amounts of the ingredients is advantageous since, when it is applied, clear adhesive joints are obtained even when working in an atmosphere with a high relative humidity. The same effect can be achieved i;f phenoxyethanol is replaced by other glycol ethers such as methyl glycol or alkyldiglycol ether. To obtain a high adhesive strength, these additives should be employed in quantities up to 10% by weight relative to the total solvent mixture.
The following Examples which illustrate the invention describe a bonding operation using nitromethane and another bonding operation using nitroethane under otherwise identical conditions. The strength result with nitromethane is given first, followed by the value obtained with nitroethane.
~1~L7~35~
E~
The longitudinal sides of two test-pieces (10 mm x 270 mm x 60 mm) of polymethyl methacrylate are dipped for approximately 60 seconds in nitromethane or nitro-ethane and joined together. Within 120 seconds the bondis stable under load, i.e. it is no longer displaceable.
By the loading of a joining part with a weight of 150 g/cm the adhesive faces are brought into intimate contact~ The load is maintained for 24 hours, After storage at room temperature for 13 days without loading 10 test-pieces (8 mm x 20 mm x 120 mm) are produced from the bonded article and the tensile strength is determined by reference to DIN 53455. Result: 36~6 N/mm and 34~8 N/mm respectively.
Example 2 The bonding operation described in Example l is carried out except that a mixture of methylene chloride and either nitromethane or nitroethane (60/40) is used as solvent adhesive. The test-piece is stable under load within 20 seconds. The tensile strength after storage for 14 days is 43.7 N/mm and 36.4 N/mm respectively.
Example 3 The bonding operation described in Example 1 is carried out except that a solvent mixture of n~ethylene chloride/nitromethane or nitroethane/phenoxyethanol (55/40/5) is used for the operation. The adhesive joint is completely clear and free of bubbles. After storage for 14 days at room temperature a strength of 43 N/mm2 and 33.7 N/mm2 respectively is achieved.
Ex~e~
S The test is conducted as described in Example 1 except that the solution applied is one of 30 parts of polymethyl methacrylate in 70 parts of a solvent mixture consisting of methylene chloride/nitromethane or nitroethane/phenoxyethanol (57/40/3). The bond is stable under load after 3 minutes. After storage for 14 days a strength of 37 N/mm and 31.8 N/mm respectively is obtained.
Claims (10)
- The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-l. A method of bonding a surface of an article made of a polymethyl methacrylate resin to another surface which comprises treating at least one of said surfaces with an adhesive composition comprising at least one nitroalkane selected from nitromethane and nitroethane, contacting the said surfaces and drying the said surfaces to form a bond between the said surfaces.
- 2. A method as claimed in claim l wherein the first-mentioned surface is treated with the said adhesive composition,
- 3. A method as claimed in claim l wherein the said adhesive composition comprises at least 30% by weight of the said nitroalkane and less than 70% by weight of at least one other organic liquid having a boiling point of not more than 200°C.
- 4. A method as claimed in any of claims l, 2 and 3 wherein the said adhesive composition comprises the said nitroalkane and dichloromethane, the weight ratio of nitroalkane to dichloromethane being in the range 30:70 to 80:20
- 5. A method as claimed in any of claims 1, 2 and 3 wherein the said adhesive composition contains up to 10%
(based on the total weight of the composition) of a glycol ether. - 6, A method as claimed in any of claims 1, 2 and 3 wherein the said adhesive composition contains a dissolved polymer and has a solution viscosity of not more than 10,000 mPa.s. at 20°C.
- 7. A method as claimed in any of claims 1, 2 and 3 wherein the said adhesive composition contains 3 to 30%
by weight of a dissolved polymer and has a solution viscosity of 500 to 2,000 mPa.s. at 20°C. - 8. A method as claimed in any of claims 1, 2 and 3 wherein the said polymethyl methacrylate resin contains at least 90% by weight of units of methyl methacrylate.
- 9. A method as claimed in any of claims 1, 2 and 3 wherein the second-mentioned surface is a surface of an article made from a polymethyl methacrylate resin.
- 10. A method as claimed in any of claims 1, 2 and 3 wherein the second-mentioned surface is a surface of an article made from a material other than a polymethyl methacrylate resin and the said adhesive composition contains a dissolved polymer and has a solution viscosity of not more than 10,000 mPa.s. at 20°C.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2737270A DE2737270C3 (en) | 1977-08-18 | 1977-08-18 | Adhesives for methacrylic ester plastics |
| DEP2737270.9 | 1977-08-18 | ||
| DEP2745420.2 | 1977-10-08 | ||
| DE19772745420 DE2745420A1 (en) | 1977-10-08 | 1977-10-08 | Solvent adhesives for methyl methacrylate! (co)polymer articles - contain nitromethane and or nitro-ethane opt. mixed with volatile liquids and dissolved polymers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1117856A true CA1117856A (en) | 1982-02-09 |
Family
ID=25772566
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000309139A Expired CA1117856A (en) | 1977-08-18 | 1978-08-11 | Method of bonding |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0000867B1 (en) |
| JP (1) | JPS6056177B2 (en) |
| CA (1) | CA1117856A (en) |
| DE (1) | DE2860616D1 (en) |
| IT (1) | IT1160596B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016026884A1 (en) * | 2014-08-21 | 2016-02-25 | Sabic Global Technologies B.V. | An adhesive composition forming structurally integral bonds with the bonding surfaces of the substrates |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4401160A1 (en) * | 1994-01-17 | 1995-07-20 | Roehm Gmbh | Adhesive for methacrylic ester plastics |
| JPH08176517A (en) * | 1994-12-22 | 1996-07-09 | Chugoku Kako Kk | Bonding by melting synthetic resin foam material |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE818205A (en) * | 1973-07-30 | 1974-11-18 | Adhesive for bonding polyurethane rubber to substrates - consists of org. isocyanate and nitroso or nitro cpd as adhesion promoter |
-
1978
- 1978-07-06 DE DE7878100311T patent/DE2860616D1/en not_active Expired
- 1978-07-06 EP EP78100311A patent/EP0000867B1/en not_active Expired
- 1978-08-11 CA CA000309139A patent/CA1117856A/en not_active Expired
- 1978-08-17 IT IT7868920A patent/IT1160596B/en active
- 1978-08-18 JP JP53100849A patent/JPS6056177B2/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016026884A1 (en) * | 2014-08-21 | 2016-02-25 | Sabic Global Technologies B.V. | An adhesive composition forming structurally integral bonds with the bonding surfaces of the substrates |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2860616D1 (en) | 1981-05-07 |
| IT7868920A0 (en) | 1978-08-17 |
| EP0000867A1 (en) | 1979-03-07 |
| JPS6056177B2 (en) | 1985-12-09 |
| EP0000867B1 (en) | 1981-04-15 |
| JPS5443276A (en) | 1979-04-05 |
| IT1160596B (en) | 1987-03-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |