JPH0316988B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a storage-stable hardener for acrylic adhesives that is miscible with acrylic resins, the hardener obtained by the method, and the use of this hardener in mixtures with acrylic resin adhesives. It is about law. Reactive acrylic adhesives are two-component adhesive systems that can be polymerized at room temperature and consist of a resin containing a compound that forms free radicals, and a curing agent. When applying these adhesives, the resin and hardener are generally applied separately to the parts to be bonded; the applied parts are then bonded and the adhesive layer is then cured. On the one hand, this simple method has many technical advantages, but on the other hand, it can lead to difficult-to-adjust variations in the strength of its adhesion. These changes in strength are
This is due to the curing process which depends on the diffusion of the curing agent into the resin layer after the resin and curing agent are combined. It has also been established that reactive acrylic resin adhesives can be cured when mixed together with curing agents (amine/aldehyde adducts formed from aniline and butyraldehyde) that are commonly used separately. . The quantitative ratio of resin to hardener required for good adhesion is approximately 100:5. However, this ratio is difficult to adjust when mechanical feeding is done in constant quantities. Furthermore, there is a large difference in the viscosity values of the resin and the hardening agent (resin 8-40Pa・s, hardening agent 200m2).
Pa·a), therefore it is difficult to homogeneously mix a dilute liquid curing agent into a viscous resin. Manual application of the adhesive components requires weighing out very different quantities, making this method too complex to be commonly used. Also, when applying the ingredients separately, it is even more troublesome.
All portions of resin and curing agent that do not adhere to each other and remain uncured due to lack of reaction partners must be removed from the adhesive product. In the specification of U.S. Patent No. 4,340,532,
An acrylic resin adhesive and hardener are described that are mixed together in a 1:1 ratio. These mixtures were developed for use in the dental field;
For industrial applications, they have the disadvantage of being difficult to mix, since one component is liquid and the other powder. In fact, curing agents containing vinyl monomers, amine/aldehyde condensates, stabilizers, and polymers are commercially available, but their viscosity increases in a relatively short period of time, resulting in poor storage stability.
Often unsuitable for application. It has been found that the curing agents produced according to the invention are viscosity-stable and even reactive, ie still capable of polymerization. The method of the present invention involves adding a thermoplastic resin or an elastomer soluble to the polymerizable monomer containing an olefinic group at a temperature of 50 to 100°C, respectively, with the addition of a stabilizer if desired; the thickening produced in this way. It consists of adding a liquid aldohyde/amine condensate to the solution; and homogenizing the solution at elevated temperatures. Preferably, the thickened solution is cooled before adding the aldehyde/amine condensate. Homogenization is preferably carried out at a temperature of 60 to 100°C. As polymerizable monomers, for example, the following are preferred: acrylate, methacrylate, styrene, chlorostyrene, 2-chloro-1,3-butadiene and 2,3-dichloro-1,3-butadiene; especially methyl-, Ethyl- or butyl methacrylate and methacrylo-2-ethoxyethyl ester are preferred. Liquid aldehyde/amine condensates that can be used are: formaldehyde, acetaldehyde,
Propionaldehyde, hexaaldehyde, heptaldehyde or crotonaldehyde and a primary or secondary, aliphatic or aromatic amine such as ethylamine, n-butylamine, n- and iso-propylamine, n-hexylamine, t
-butylamine, p-toluidine, xylidine or benzylamine, as well as diethylamine and diphenylamine. Preferably, a reaction product consisting of aniline and butyraldehyde is used, in which per mole of aniline:
1 to 3.5 moles of butyraldehyde are used, preferably 1.5 to 3.0 moles. As stabilizers, preference is given to using quinoline-like compounds, especially quinoline itself in amounts of 0.005 to 0.5% by weight, based on the hardener. Whether or not it is necessary to use a stabilizer depends on the reactivity of the monomeric compound. For example, when using butyl acrylate, no stabilizer is required (although it can of course be present); whereas, when using, for example, methyl methacrylate, a stabilizer is required. Preferred thermoplastic resins for use are polyacetals, polyacrylates, polymethacrylates, polystyrenes or polyamides, or copolymers of styrene and acrylates or methacrylates, copolymers of styrene and butadiene or copolymers of styrene and isoprene, or copolymers of styrene, butadiene and Terpolymers from acrylonitrile, from 5 to 85% by weight, preferably 5% by weight, based on the curing agent.
It is used in an amount of 35% to 35% by weight. Preferred elastomers include: polyurethane, butyl rubber or butadiene/acrylonitrile copolymers and are used in amounts of 5 to 85%, preferably 5 to 35% by weight, based on the curing agent. The amount of thermoplastic resin or elastomer in the curing agent depends on the desired viscosity of the curing agent. The value of this viscosity is advantageously matched to the viscosity of the acrylic resin adhesive, i.e. from about 4 to 30 Pa·s.
It is. The method of the invention can also be carried out with the addition of transition metal compounds as promoters during bonding. Such compounds include metal-containing compounds in the form of chelate compounds, such as β-diketones or ethylene- or propylene diamines, or metal-containing compounds in the form of organic acid or alcohol compounds, such as naphthenates (e.g. cobalt, as nickel or manganese-containing compounds),
Included are octoates (eg, as copper-containing compounds), hexoates, and propionates (eg, as iron-containing compounds). Preferred materials are acetylacetonates of vanadium, copper, cobalt and iron. For example: Cu(II)-acetylacetonate, Cu-p-toluenesulfinate and Cu-naphthenate. They are,
It is added in an amount of 0.0005 to 1.0% by weight based on the curing agent. Surprisingly, even with the addition of accelerators of the aforementioned type, the present curing agent mixture remains stable with respect to viscosity and activity, and also in the presence of quinone as stabilizer. It is. Acrylic acid resin adhesives can also be manufactured, for example, according to US Pat. No. 4,278,106. Production of acrylic acid resin adhesive A: 58 parts by weight of methyl methacrylate, methacrylic acid
17 parts by weight of ethylene glycol dimethacrylate, 0.5 parts by weight of quinone and 27 parts by weight of acrylonitrile/butadiene/styrene copolymer powder are dissolved at 50° C. under nitrogen. Subsequently, 2 parts by weight of chlorsulfophenylmaleimide are added at room temperature and the mixture is stirred for 1 hour. Then 1 part of cumene hydroperoxide and 0.5 part of butylene glycol diglyside are added and the mixture is homogenized. The Bruckfield viscosity of this acrylic acid resin adhesive A (measured using spindle No. 4 at 50 r.p.m.) is 8 to 12 Pa.
It is s. Based on the total amount of this curing agent, the amount of
80% by weight, preferably 60 to 80% by weight of polymerizable monomer, 5 to 25% by weight, preferably 10 to 80% by weight
18% by weight aldehyde/amine condensate, 5 to
It contains 85% by weight, preferably 10 to 20% by weight of thermoplastic resin or elastomer, and optionally stabilizers and/or metal compounds in the specified amounts. "Parts" in the following examples represent parts by weight. Example 1: Production of a slow-release curing agent that can be mixed with a resin adhesive at a ratio of 1:1 64.7 parts of methyl methacrylate and 0.3 parts of quinone were mixed at room temperature under nitrogen in a volumetric flask with a stopper.
Mix thoroughly. Then, 20 parts of polyacetal are added and the liquid mixture is stirred at 80°C for 1 hour (here, polyacetal is made from vinyl alcohol and butyraldehyde and has a molecular weight of
34,000 to 38,000; measured with an Oswald viscometer,
The viscosity of a 10% solution in 95% ethanol is 55mPa・
s). The solution was then cooled to room temperature, followed by
The condensation product formed from aniline and butyraldehyde (“Vanax 808”) is approx.
Add 15 parts of a product consisting of 40%. 80% of this solution
Homogenize for 2 hours at °C and cool. This curing agent can be mixed with the resin adhesive A at any mixing ratio within the range of 2:1 to 1:2 (accurate metering is not required) depending on the desired curing time.
The Bruckfield viscosity of this curing agent is 8 Pa・s before storage and 10 Pa・s after storage at 60°C for 7 days.
It is s. Example 2: Preparation of a fast-acting curing agent that is miscible with the resin in a 1:1 ratio. Implement method 1. This Burtskfield viscosity is 6Pa before storage.
s, and 7 Pa·s after storage at 60°C for 7 days. Example 3: The method described in Example 2 is carried out, except that 0.005 part of copper p-toluenesulfinate is mixed instead of copper acetylacetonate. This Burtskfield viscosity is 9Pa before storage.
s, and remained unchanged after storage at 60°C for 7 days. Example 4: The same amount of polyurethane elastomer (the Bruckfield viscosity of this polyurethane in a 15% solution in ethyl methyl ketone at 23° C. is 1.6 to 2 Pa·s) is used instead of 20 parts of polyacetal. It is carried out in the manner described in Example 1. This Burtskfield viscosity is
After storage for 7 days at 26Pa・s and 60℃
It is 22Pa・s. Example 5: The procedure is carried out as described in Example 4, except that 0.005 part of copper acetylacetitonate is added to the amine/aldehyde condensate. Before storage, this Burckfield viscosity is
After storage for 7 days at 28Pa・s and 60℃
It is 20Pa・s. The properties of a 1:1 mixture of acrylic resin adhesive A and the curing agents of Examples 1 to 5 are shown in the following table. For its curing, fresh acrylic resin A is used in each case. The substrate used is a degreased aluminum sheet. To determine the initial adhesion, the curing agent is
Use freshly prepared. This initial adhesion is
It is measured by the time from when the coated sheets are placed together until the sheets just adhere to each other without separating. In determining the tensile shear strength, for mixtures with acrylic resins, the value with a freshly prepared hardener is in the first box (“0 value”) and the same hardener at 60 °C. The values stored for 7 days are shown in the second frame (7 days/60°C). This measurement is performed after mixing at room temperature (“RT”) or
Perform for 60 minutes and 24 hours.

[Table] Examples 6 to 39: 64.7 parts of methyl methacrylate and 0.3 parts of quinone were added in a volumetric flask with a stopper at room temperature under nitrogen.
Mix thoroughly; and then add 20 parts of polymerizable monomer as a thickener. After these components have dissolved, 15 parts of the amine/aldehyde adduct and, if desired, the metal salt are added and the mixture is homogenized at 80° C. for 2 hours. The quinone + amine/aldehyde condensation product forms a precipitate that is insoluble in methyl methacrylate, so close observation after addition of the protruding material is very important. In the table, the initial value of the viscosity of the prepared curing agent measured according to Bruckfield and 7
Values are shown after storage for one day.

【table】

[Table] The table shows examples 6 to 39 at room temperature.
The tensile strength of the adhesive phase with acrylic acid resin A after curing for 45 minutes and 24 hours is shown, where the value using a freshly prepared stabilizer is in the first frame (HA), and the value using the same curing agent at 60 The values stored at ℃ for 7 days are shown in the second box (HB). In these tests, degreased aluminum sheets were glued.

【table】

【table】

【table】

[Table] Delamination = delamination, that is, something that did not adhere. The table also shows that metal salts have an adhesion promoting effect.

Claims (1)

[Claims] 1. A polymerizable monomer having an olefinic group, optionally containing a stabilizer, at a temperature of 50 to 100°C.
and adding a thermoplastic resin or elastomer soluble in each of the monomers; adding a liquid aldehyde/amine condensate to the thickened solution thus formed; and homogenizing the solution at elevated temperatures.
A method for producing a storage stable curing agent for reactive acrylic adhesives that is miscible with acrylic resin adhesives. 2. The method of claim 1, wherein the thickened solution is cooled before adding the aldehyde/amine condensate. 3. The method according to claim 1, wherein the homogenization is carried out at a temperature of 60 to 100°C. 4 Add to the mixture, based on the total amount of curing agent.
Claim 1: A transition metal complex compound is added as a curing accelerator in an amount of 0.0005 to 1.0% by weight.
The method described in section. 5 The polymerizable monomer used is acrylate, methacrylate, styrene, chlorostyrene, 2-chloro-1,3-butadiene or 2,3-dichloro-1,3-butadiene, according to claim 1. Method. 6. Process according to claim 5, using methyl-, ethyl- or butyl methacrylate or methacrylic acid-2-ethoxy-ethyl ester. 7. The thermoplastic resin used is a polyacetal, polyacrylate, polymethacrylate, polystyrene or polyamide, or a copolymer formed from styrene and acrylate or methacrylate, styrene and butadiene or styrene and isobrene, based on the amount of curing agent. A method according to claim 1, in which an amount of 5 to 95% by weight is used. 8. Process according to claim 1, in which the elastomer used is polyurethane, butyl rubber or butadiene/acrylonitrile copolymer in an amount of 5 to 85% by weight, based on the amount of curing agent. 9 The liquid aldehyde/amine condensate used is
The method according to claim 1, which is produced from aniline and butyraldehyde. 10. The method according to claim 1, wherein quinone as a stabilizer is added to the polymerizable monomer. 11 A polymerizable monomer having an olefinic group, optionally containing a stabilizer, is heated at a temperature of 50 to 100°C.
by adding a thermoplastic resin or elastomer, each of which is soluble in the monomers at °C; adding a liquid aldehyde/amine condensate to the thickened solution thus formed; and homogenizing the solution at elevated temperatures. A curing agent for reactive acrylic adhesives produced. 12 10 to 90% by weight based on the total amount
of a polymerizable monomer, 5 to 25% by weight of an aldehyde/amine condensate, 5 to 85% by weight of a thermoplastic resin or elastomer, optionally 0.0005 to 1.0% by weight of a transition metal complex compound, and optionally 0.005 to 0.5% by weight of a transition metal complex compound. 12. A curing agent according to claim 11 containing % by weight of stabilizer. 13 A polymerizable monomer having an olefinic group, optionally containing a stabilizer, is heated at a temperature of 50 to 100°C.
by adding a thermoplastic resin or elastomer, each of which is soluble in the monomers at °C; adding a liquid aldehyde/amine condensate to the thickened solution thus formed; and homogenizing the solution at elevated temperatures. The curing agent produced is reactive, in the form of a mixture containing a reactive acrylic resin adhesive, and in which the quantitative ratio of acrylic resin adhesive to curing agent is from 2:1 to 1:2. Usage for acrylic acid glue.