Eco-friendly adhesive formulations containing 2-methyltetrahydrofuran

Abstract

The present invention relates to adhesive formulations, preferably based on polychloroprene, containing preferably bio-based solvents or solvent mixtures, which have long open times with high solution viscosity.

Description

[Technical field]

[0001] The present invention relates to an adhesive formulation preferably based on polychloroprene, preferably containing a bio-based solvent or solvent mixture having a long open time with high solution viscosity, which adhesive formulation is eco-friendly. [Background technology]

[0002] Solvent-based contact adhesives have a long history and are known for their ease of handling: they can be easily applied, for example by brush or roller, the solvent has a degreasing effect, which makes application easier compared to dispersion-based systems, and the high initial strength allows the bonded parts to be used immediately without fixing.

[0003] Solvent-based contact adhesives can be applied in different ways: wet-in-wet bonding, heat or solvent reactivation or contact bonding. For the preferred method, the adhesive is applied to both adherends in contact bonding. After application, the solvent starts to evaporate. The minimum drying time is defined as the moment when most of the solvent has evaporated and bonding is first possible. The adherends can then be bonded (contact bonding process) within the open time (contact bonding time) with the highest possible pressure. The open time ends when the adhesive layer is too dry to press the two substrates together and bond them together. A characteristic feature of contact adhesives is that bonding within the open time results in an immediate bond with high initial strength. When using contact adhesives, no clamping of the adherends is required.

[0004] Solvent-based contact adhesives can be based on a variety of polymers, such as polychloroprene, nitrile rubber, polyurethane, ethylene-propylene-diene-rubber, styrene-butadiene-styrene or styrene-isoprene-styrene block copolymers, among others.

[0005] Solvent-based contact adhesives with polychloroprene as their base are notable for their adhesion to a variety of different substrates, high initial strength, long contact adhesion time, good adhesion and self-adhesion, as well as resistance to chemicals, water, weathering and ozone. They have therefore been established for many years in applications within the footwear, furniture, construction, DIY and automotive industries.

[0006] Suitable solvents for contact adhesives are generally organic solvents and mixtures thereof. They are, for example, chlorinated or non-halogenated aliphatic, aromatic or aliphatic-aromatic hydrocarbons, ketones or esters. In the early days of polychloroprene-based contact adhesives, chlorinated solvents were the first choice. Later, for health reasons, aromatic solvents took over. Preferably, cyclohexane, methylcyclohexane, petroleum-volatile solvents, acetone, 2-butanone, ethyl acetate, propyl acetate and butyl acetate are used. The amount of solvent or solvent mixture used is, for example, 60-95% by weight, preferably 65-90% by weight, more preferably 70-85% by weight, based on the adhesive composition. The antiaging agents used are mainly sterically hindered phenols, for example Vulkanox BHT.

[0007] One important property of a solvent-based contact adhesive is the open time. A long open time is essential for convenient use of a solvent-based adhesive. A long open time allows for application over large areas (e.g., when flooring or roofing). The entire area can be coated at the same time, after which the substrate can be applied. Furthermore, it is possible to make many substrates, store them, and later join the substrates at once. For these applications, an open time of at least 3.5 hours is convenient.

[0008] The use of terpene phenolic resins to increase open time is described in (Non-Patent Document 1). (Non-Patent Document 1) teaches the use of "a resin material with a softening point of 145°C or higher, obtained by polymerizing a cracked oil fraction of crude oil or its distillation products" for this purpose. However, neither type of resin is preferred as it causes poor heat resistance, and alkylphenolic resins are required for achieving advantageous heat strength ((Non-Patent Document 1)). (Non-Patent Document 2) discloses the addition of halobutyls to adhesive formulations to increase open time, but the addition of another polymer component is not preferred as compatibility (phase separation) problems may occur. Furthermore, the undesirable use of halogenated or aromatic solvents is required ((Non-Patent Document 2), p. 4). Furthermore, halobutyls reduce the polarity of the adhesive. As the halobutyl content increases, the peel strength at ambient temperature decreases ((Non-Patent Document 2), p. 6, Figure IV).

[0009] The most important property when applying an adhesive is its viscosity. Many end users prefer a high viscosity of the final adhesive to allow good application without dripping, to prevent unwanted flow of the adhesive and absorption of the adhesive by porous substrates such as foams. Furthermore, a high viscosity allows the adhesive to be applied on vertical or inclined surfaces without dripping. Viscosities above 7000 mPas are perceived as convenient for most applications.

[0010] In order to increase the viscosity, (Non-Patent Document 2) teaches the use of a base polymer with a high molecular weight, but this is not preferred because the solvation time also increases. The addition of a higher component ratio of base polymer is also possible, but it may lead to solubility problems and is an unnecessary waste of resources. (Patent Document 3) teaches the use of methylcyclohexane as a replacement for toluene and cyclohexane. However, the viscosity and open time achieved are not sufficient.

[0011] US Pat. No. 5,399,633 discloses a solvent-borne composition based on polychloroprene. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] U.S. Patent No. 3,933,719A [Patent Document 2] U.S. Patent No. 3,488,315A [Patent Document 3] Japanese Patent Publication No. 2003226852 [Patent Document 4] Canadian Patent No. 2527561 [Non-patent literature]

[0013] [Non-Patent Document 1] Handbook of Adhesive,Skeist I,Vol.3,New York,1990,p.295 [Non-Patent Document 2] “Baypren adhesives product portfolio”,ARLANXEO,Dormagen,2021 Summary of the Invention [Problem to be solved by the invention]

[0014] From each and every point of view, the known compositions are unsatisfactory. There is a need in the market for a solvent-based contact adhesive having a long open time of at least 3.5 hours and a high viscosity of at least 7000 mPas. It is therefore an object of the present invention to provide an improved composition. [Means for solving the problem]

[0015] The purpose of this is to -polychloroprene; and a first organic solvent which is 2-methyltetrahydrofuran; This has been achieved by providing a composition comprising:

[0016] Surprisingly, it has been found that the use of 2-methyltetrahydrofuran in contact adhesives solves this problem. 2-Methyltetrahydrofuran is capable of dissolving polychloroprene both as a single solvent and in mixtures with other solvents. Furthermore, adhesives made with 2-methyltetrahydrofuran or mixtures of 2-methyltetrahydrofuran with other solvents provide a desirable long open time in combination with a high viscosity of the adhesive.

[0017] Furthermore, it has been surprisingly found that 2-methyltetrahydrofuran, which is produced from waste materials from corn production, can be used as a solvent for CR-based adhesives, providing a sustainable alternative to conventional solvents. 2-Methyltetrahydrofuran, by itself or in combination with other (bio-based) solvents such as ethyl acetate, is not only capable of dissolving CR, but also provides an adhesive with high viscosity and long open time.

[0018] A long open time is important for easy application of the adhesive.

[0019] Higher viscosities at a given polychloroprene concentration are preferred because they avoid unnecessary waste of resources and result in more economical formulations.

[0020] In particular, the technical objective is achieved by using 2-methyltetrahydrofuran or a mixture of 2-methyltetrahydrofuran with other solvents as a solvent for polychloroprene-based adhesives. A mixture of 2-methyltetrahydrofuran and ethyl acetate is preferred. A mixture of 2-methyltetrahydrofuran and ethyl acetate in a ratio of 2-methyltetrahydrofuran (5-100% by weight) to ethyl acetate (0-95% by weight) is more preferred. Preferably, the solvent is bio-based. For example, 2-methyltetrahydrofuran and ethyl acetate are available from non-fossil resources, adding value to a sustainable solution in the future.

[0021] In particular, the present invention provides a solvent-based, preferably bio-based, solvent-based adhesive formulation having a convenient combination of high viscosity and long open time. Preferably, the composition according to the present invention has a viscosity >7000 mPas, preferably >7000 mPas and <20000mPas; or > 8000 mPas, preferably >8000 mPas and <20000 mPas (in each case at a temperature of 20-25°C, preferably at about 23°C, or more preferably exactly at 23°C) and / or an open time of >3.5 hours, preferably >3.5 hours and <10.5 hours; or >5 hours, preferably >5 hours and <10.5 hours.

[0022] Those skilled in the art will be aware of suitable methods for determining viscosity and open time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] In a preferred embodiment, the open time is 160 g / m DINA4 with a doctor blade width of 10 cm and a gap width of 200 μm. 2 It is determined by applying the composition on a piece of kraft paper. The paper is cut into strips 3 cm wide. Once applied, the solvent begins to evaporate. After a preset time, the adhesive layers on the strips are pressed together. The adhesive is within its open time as long as the glued papers cannot be separated without destroying the paper. The open time is exceeded if the papers can be separated after bonding. The maximum open time of an adhesive is the time difference between the application of the adhesive and the moment when adhesion was last possible.

[0024] In a preferred embodiment, the solution viscosity of the composition is measured with a Brookfield Digital Rotational Viscometer LV DV II+ with spindle LV2 (62) and equipped with guard legs. The composition is conditioned at 23° C. and measurements are carried out at 23° C. at the highest possible rotational speed. The results of the measurements are reported in mPa * Denoted by s.

[0025] Thus, in a first aspect, the present invention relates to a solvent-based contact adhesive composition comprising a solvent mixture comprising a first organic solvent, 2-methyltetrahydrofuran, in an amount of 5-100% by weight, preferably 10-100% by weight, based on the total weight of the solvent mixture. When the solvent mixture comprises the first solvent, 2-methyltetrahydrofuran, in an amount of 100% by weight, based on the total weight of the solvent mixture, the terms "solvent mixture" and "first organic solvent, 2-methyltetrahydrofuran" are synonymous.

[0026] Polychloroprene (PCP, CR) Polychloroprene is also known as neoprene and is available (commercially) to those skilled in the art.

[0027] In the context of the present invention, the term polychloroprene preferably means a polymer obtained by emulsion polymerization of chloroprene (2-chloro-1,3-butadiene), alone or together with other monomers copolymerizable with chloroprene, such as 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, 1,3-butadiene, isoprene, acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, sulfur and styrene. The proportion of these comonomers is usually less than or equal to 25%, preferably less than or equal to 20%, more preferably less than or equal to 15% and most preferably less than or equal to 10% relative to the total mass of the copolymer.

[0028] Suitable emulsifiers for the production of PCP are basically all compounds and mixtures thereof which sufficiently stabilize emulsions, such as water-soluble salts, in particular the sodium, potassium and ammonium salts of long-chain fatty acids, rosin and rosin derivatives, relatively high molecular weight alcohol sulfates, arylsulfonic acids, formaldehyde condensates of arylsulfonic acids, non-ionic emulsifiers based on polyethylene oxide and polypropylene oxide, emulsifying polymers such as polyvinyl alcohol (see, for example, US Pat. No. 2,234,215).

[0029] The production of polychloroprene is a procedure with a long history. It is achieved by radical emulsion polymerization in an alkaline aqueous medium and at temperatures mainly between 10 and 45 ° C. The polymerization temperature influences the microstructure of the resulting polymer. The lower the polymerization temperature, the higher the proportion of monomer units incorporated into the chain in the trans configuration. The higher the proportion of monomer units in the trans configuration, the higher the tendency of polychloroprene to crystallize.

[0030] Polymerization is stopped at 60-100% conversion and unconverted monomer is removed by devolatilization. To isolate the solids, the dispersion is first adjusted to a pH of 5.5-7.0 by addition of dilute acetic acid. The polychloroprene is then recovered by precipitation of the dispersion on chilled rolls (approximately -15°C) (freeze flocculation). The thin frozen polychloroprene layer is thawed, washed, dried and collected to form strands which are chopped into chips. Polychloroprene finds use in applications such as rubber articles and in contact adhesives and sealants.

[0031] For the production of adhesives, strongly crystallizing types of polychloroprene are mainly used, which can be obtained by emulsion polymerization at low temperatures (below 15°C). Furthermore, polychloroprene with a moderate tendency to crystallize can be used, which can be obtained by emulsion polymerization at temperatures between 15 and 40°C. The adhesives produced therefrom result in adhesive bonds which have high initial strength and which harden rapidly. These properties are particularly important in all cases where the adhesive bond is exposed to high material stresses, for example when gluing highly arched soles in the shoe industry or curved surfaces in the furniture industry, and especially when the glued articles have to undergo further processing, for example on conveyor belts. The preferred types of polychloroprene used according to the invention have a solution viscosity of 50 to 15,000 mPas at 23°C (10% by weight in toluene).

[0032] In a preferred embodiment, the content of polychloroprene is at least 5% by weight, preferably 5-60% by weight, more preferably 10-40% by weight, even more preferably 15-30% by weight, in each case relative to the total weight of the composition according to the invention. In another preferred embodiment, the content of polychloroprene is at most 10% by weight or at most 25% by weight or at most 50% by weight or at most 75% by weight or at most 90% by weight, in each case relative to the total weight of the composition according to the invention.

[0033] In a preferred embodiment, the composition according to the invention is an adhesive composition and / or a sealant composition.

[0034] solvent The composition according to the present invention includes a first organic solvent that is 2-methyltetrahydrofuran.

[0035] 2-Methyltetrahydrofuran is also known as 2-Me-THF.

[0036] 2-Methyltetrahydrofuran has the following formula: [ka] It is represented by:

[0037] The two enantiomers of 2-methyltetrahydrofuran, namely, [ka] There are (R) and (S) enantiomers, represented by ((R) enantiomer on the left, and (S) enantiomer on the right).

[0038] 2-Methyltetrahydrofuran is (commercially) available to those skilled in the art.

[0039] In a preferred embodiment, 2-methyltetrahydrofuran is understood to include the racemate, the (R) enantiomer and the (S) enantiomer.

[0040] In a preferred embodiment, the composition according to the present invention further comprises a second organic solvent which is ethyl acetate.

[0041] In a preferred embodiment, the composition according to the present invention comprises a mixture of a first organic solvent that is 2-methyltetrahydrofuran and a second organic solvent that is ethyl acetate; - the content of the first organic solvent, which is 2-methyltetrahydrofuran, is 5 to less than 100% by weight, based on the total weight of the mixture, and the content of the second organic solvent, which is ethyl acetate, is 0 to more than 95% by weight, based on the total weight of the mixture; The total amount of the first organic solvent, which is 2-methyltetrahydrofuran, and the second organic solvent, which is ethyl acetate, is preferably 100% by weight based on the total weight of the solvent mixture.

[0042] In a preferred embodiment, the content of the first organic solvent, which is 2-methyltetrahydrofuran, is in each case at least 10% by weight, preferably from 40 to 95% by weight, more preferably from 60 to 90% by weight and more preferably from 65 to 85% by weight, relative to the total weight of the composition according to the invention.

[0043] In a preferred embodiment, the total amount of the first organic solvent, which is 2-methyltetrahydrofuran, and the second organic solvent, which is ethyl acetate, is in each case at least 10% by weight, preferably 40 to 95% by weight, more preferably 60 to 90% by weight, and more preferably 65 to 85% by weight, based on the total weight of the composition according to the invention.

[0044] In a preferred embodiment, the first organic solvent, which is 2-methyltetrahydrofuran, is bio-based and / or the second organic solvent, which is ethyl acetate, is bio-based.

[0045] In a preferred embodiment, the first organic solvent, 2-methyltetrahydrofuran, is produced or obtained from a non-fossil resource and / or the second organic solvent, ethyl acetate, is produced or obtained from a non-fossil resource.

[0046] In a preferred embodiment, the first organic solvent, which is 2-methyltetrahydrofuran, is generated or obtained from waste products of corn production.

[0047] In a preferred embodiment, the composition according to the invention comprises 2-methyltetrahydrofuran as the only organic solvent.

[0048] In a preferred embodiment, the composition according to the present invention does not contain any solvent other than the first organic solvent, which is 2-methyltetrahydrofuran, and the second organic solvent, which is ethyl acetate.

[0049] However, in another preferred embodiment, the composition according to the invention further comprises a solvent, i.e. in addition to the first organic solvent being 2-methyltetrahydrofuran. The optional second organic solvent is an alkyl acetate, preferably ethyl acetate. In addition to or instead of the alkyl acetate, preferably ethyl acetate, other organic solvents may be present. These further solvents are described in the following paragraphs.

[0050] The organic solvent is a carbon-containing solvent. Polychloroprene type adhesives are soluble in many organic solvents and solvent mixtures. In the composition according to the invention, the polychloroprene is therefore present at least partially in dissolved state. The solvent or solvent mixture used in the preparation of the adhesive is selected on the basis of commercial and technical factors, in particular the solvent being: - the viscosity of the adhesive, - processability, e.g. brushability, the compatibility of the adhesive with any crosslinking agents added; - adhesive properties when stored at low temperatures, -Phase separation occurs during storage of resin-containing adhesives, - Wetting of the surfaces to be bonded, - Drying of adhesive film, - the contact adhesion time of the adhesive film, and - the cure speed of the adhesive bond, It must be taken into account that it has a significant effect on

[0051] Apart from the above mentioned effects on the technical properties of the adhesive, the physiological effects of the solvent and its flammability must also be taken into account.

[0052] Suitable solvents include polar and non-polar solvents. According to the present invention, a polar solvent is a solvent whose solubility in water at 20° C. is greater than 0.1% by weight relative to the amount of water. Such solvents include, for example, halogenated aliphatic hydrocarbons, aliphatic esters, such as alkyl acetates, for example methyl acetate, ethyl acetate, n-butyl acetate, aliphatic ketones, for example acetone, methyl ethyl ketone, and alcohols, such as n-butanol. The polar solvent is preferably a solvent that is miscible at room temperature with aliphatic or aromatic hydrocarbons without phase separation and preferably in the desired mixing ratio.

[0053] According to the present invention, a "non-polar solvent" is understood to be a solvent that is essentially immiscible with water, i.e. its solubility in water at 20°C is less than 0.1% by weight relative to the amount of water. Conversely, for example less than 0.1% by weight of water dissolves in such a solvent at 20°C. Preferred solvents / mediums are also those whose dielectric constant (DC) is <5, in particular whose DC is <3. The following may be used, for example: aliphatic and / or aromatic hydrocarbons, paraffinic, naphthenic and aromatic oils and waxes with variable chain length, degree of branching and molecular weight, as well as long-chain esters, alcohols, ketones, ethers, halogenated aliphatic and / or aromatic hydrocarbons, and combinations / mixtures thereof. Preferred are mixtures of aliphatic, branched, linear, cyclic or aromatic hydrocarbons, such as pentane, hexane, cyclohexane, methylcyclohexane, heptane, octane, benzene, toluene, xylene, etc., and solvent naphtha or gasoline, etc.

[0054] According to the invention, mixtures of the abovementioned polar and non-polar solvents are particularly preferred. Preferred solvent mixtures consist of aliphatic esters and / or ketones and aliphatic and / or aromatic hydrocarbons.

[0055] Optional Ingredients The polychloroprene composition according to the invention may also optionally contain auxiliaries and / or additives which are usually used in adhesives, such as, for example, dispersants:

[0056] Dispersants A dispersant may be added to the composition according to the present invention.

[0057] Suitable dispersants are long chain (C5-C 20 ) carboxylic acids and sulfonic acids.

[0058] Preferred dispersants are long chain (C5-C6) dispersants such as oleic acid. 20 ) carboxylic acids. Furthermore, stabilizers, such as, for example, mono- or polyhydric alcohols or polyethers, may be added to the compositions according to the invention.

[0059] Particularly preferred variants of the dispersant are those resulting from the reaction of MgO with at least one phenolic resin. Phenolic resins are synthetic resins obtained by condensing phenol with an aldehyde, in particular formaldehyde, by derivatizing the condensate obtained, or by adding phenol to unsaturated compounds such as natural resins. Condensation products of phenol and aldehyde are preferably used. Preferably, alkylphenols (cresol, xylenol, nonylphenol, t-butylphenol and octylphenol) and aryl derivatives and dihydric phenols are used in addition to phenol as the phenolic component. Alkylphenolic resins are particularly preferred.

[0060] Filler The most diverse types of fillers can be added to the polychloroprene adhesive in any desired amount. Highly filled mixtures are mainly gap-filling types of luting clays. Suitable fillers are, for example, kaolin, chalk, barite, quartz powder, asbestos powder, carbon black and silica.

[0061] Approximately 50-100% of additives based on the polychloroprene or polychloroprene rubber content are usually used. Kaolin or chalk is added to such adhesives, for example. They are used for gluing floor coverings.

[0062] In rare cases, carbon black alone may be used because of its color, but the carbon black and silica filler increase the cohesive strength of the adhesive film. Too much silica filler will impair contact adhesion, resulting in no all-through adhesion.

[0063] However, if the filler needs to be distributed as precisely as possible, it should be incorporated using a roller or, better still, an internal mixer. Pasting in machines normally used for coating is also possible.

[0064] If the adhesive is to be pigmented any particular shade, the color pigment can be incorporated in the same manner as the fillers.

[0065] resin By using solutions of strongly crystallizing types of polychloroprene that simply contain metal oxides as additives, high strength compounds are obtained without the use of further additives.

[0066] These adhesives have rapid curing capabilities, however, their short contact adhesion period is less advantageous.

[0067] By adding resins, the contact adhesion period can be adjusted over a wide range and the curing time can be accelerated. The final state of crystallization of the polychloroprene is not substantially impaired by the resin, resulting in high cohesive strength of the adhesive film. There are liquid, plastic, hard and brittle resins. They can be used to increase or decrease the elasticity of the adhesive film to match the material to be bonded. The resins are soluble without causing a significant increase in viscosity. Therefore, they can be contained in the adhesive in relatively large amounts.

[0068] Many natural and synthetic resins, such as, for example, ethylene, glycerol and pentaerythritol esters of unmodified, hydrogenated and dimerized rosins, meet the basic requirement of compatibility with polychloroprene solutions. The same applies to rosin esters, modified with phenolic resins and subsequently esterified, of the kind obtained from low molecular weight phenol / formaldehyde condensates and rosins, as well as terpene-phenol and coumarone resins. As already mentioned above, their compatibility with heat-reactive alkylphenolic resins obtained from alkylphenols, such as, for example, butyl or octylphenol, and formaldehyde in alkaline medium is particularly important.

[0069] In a preferred variant of the invention, the composition preferably contains at least one additional polymer or resin, which is preferably an alkylphenol / formaldehyde resin of the type available on the market, such as, for example, Alresen® PA565, SP134 (SI Group).

[0070] Resins are typically added in amounts of about 10-50% based on the polychloroprene or polychloroprene rubber content, but higher amounts can be used.

[0071] Terpene phenolic resins, low melting rosin esters and coumarone resins, among others, can be used to extend the contact bond duration. Rapid cure of the bond, i.e. the fastest possible gain in final strength, can be achieved with high melting rosin esters or heat-reactive alkylphenolic resins, but this reduces the contact bond duration.

[0072] Chlorinated Rubber When terpene phenolic resins, low melting rosin esters and / or coumarone resins are used as tackifiers in the manufacture of polychloroprene adhesives, the early strength of the bond can be significantly increased by adding 5-10 parts of a chlorinated rubber such as Pergut® S40.

[0073] Chlorinated rubber is preferably used.

[0074] Anti-aging agents Polychloroprene itself is much more resistant to aging than many of the resins used in the manufacture of adhesives. Rosin esters, coumarone resins and terpene phenolic resins are unsaturated compounds and therefore subject to oxidation over time. This is first manifested by embrittlement or softening of the adhesive layer in the peripheral areas of the bond and may ultimately result in complete destruction of the adhesive bond. By the addition of suitable antioxidants, aging of polychloroprene adhesive bonds can be prevented.

[0075] Sterically hindered phenols such as Vulkanox® KB and Vulkanox® SKF are optimally suited for resin containing polychloroprene adhesives. At 2% relative to the polymer, these antioxidants provide effective protection and their tendency to discolor under the action of light and contact is low.

[0076] Furthermore, ZnO can be added, which acts as an anti-aging agent, in particular as an agent for absorbing HCl by forming ZnCl2. Therefore, MgO is preferably added, which inactivates ZnCl2 by forming oxychlorides, a catalyst for the undesired crosslinking of polychloroprene.

[0077] However, in a preferred embodiment, the composition according to the invention does not comprise ZnO and / or MgO.

[0078] In a preferred embodiment, the composition according to the invention does not contain any metal oxides.

[0079] Polyisocyanate-based crosslinkers In the case of highly crystallizing types of polychloroprene, the cohesive strength of the adhesive bond is significantly increased by its crystallization. However, this crystallization is temperature dependent. Under the action of heat the adhesive film recrystallizes and therefore loses strength. The resistance of the adhesive bond to the action of heat is improved if thermoreactive phenolic resins are added to the adhesive. They increase the heat resistance to about 100-110 ° C.

[0080] If higher heat resistance is required, it is advisable to add polyisocyanates, such as Desmodur, to the adhesive solution before its application. Due to the crosslinking that starts immediately upon addition of polyisocyanates, the immediate strength of the adhesive bonds increases and they cure more quickly. Furthermore, the addition of polyisocyanates improves adhesion to many difficult-to-glue substrates.

[0081] Adhesives containing polyisocyanates must be applied within a few hours before the reaction has progressed to such an extent that gel formation occurs.

[0082] Further additives containing magnesium or zinc The addition of magnesium oxide and zinc oxide to polychloroprene-based adhesives is known from the prior art. The presence of these metal oxides has a beneficial effect on the storage properties of the adhesive and on the stability of the adhesive bond.

[0083] This effect is due to the fact that polychloroprene has a tendency to cleave small amounts of hydrogen chloride during storage, for which the metal oxide acts as a receptor.

[0084] The addition of about 4% each of magnesium oxide and zinc oxide, based on the polychloroprene or polychloroprene rubber content, has proven advantageous.

[0085] Instead of the oxides, carbonates of these metals are also sometimes used; zinc carbonate has a more transparent appearance in the adhesive than zinc oxide.

[0086] Preferred Additives The composition according to the invention preferably further comprises adhesive auxiliary components and / or additives.

[0087] The compositions according to the invention may further contain fillers, dispersants, crosslinkers, colour pigments, metal oxides (e.g. ZnO or MgO), anti-ageing agents, polymers, resins (e.g. reactive phenolic resins or alkylphenolic resins), vulcanising agents, vulcanisation accelerators, antioxidants, softeners and / or chlorinated rubbers, preferably in an amount of 5 to 50% by weight, more preferably 5 to 15% by weight or 15 to 30% by weight, based in each case on the total polychloroprene content and / or the total weight of the composition.

[0088] Further aspects of the invention In a second aspect, the present invention provides a method for producing a pharmaceutical composition comprising the steps of: (a) providing polychloroprene; (b) - in biobased form; and / or - from non-fossil resources, and / or providing at least a portion, preferably all, of said 2-methyltetrahydrofuran from waste products of corn production; (c) - in biobased form; and / or - optionally providing at least a portion, preferably the entire amount, of said ethyl acetate from a non-fossil resource; (d) mixing the ingredients according to steps (a), (b) and optionally (c); The present invention relates to a process for producing the composition, comprising:

[0089] In a preferred embodiment, the composition produced is an adhesive and / or sealant composition.

[0090] The most diverse types of machines can be used for the production of the composition according to the invention. As a rule, the machines used are stirring or kneading devices which grind and dissolve the components of the adhesive.

[0091] In a preferred variant of the invention, when preparing the composition according to the invention, only a part of the total specified amount of solvent - approximately 80% or 90% - is initially introduced into the dissolving machine, and after preparation the required viscosity can be adjusted by adding the remaining solvent. The polychloroprene and optionally the fillers, resins and anti-aging agents are added to the initially introduced solvent, continuing with stirring.

[0092] In a third aspect, the present invention relates to the use of a composition according to the invention as an adhesive and / or sealant.

[0093] In a fourth aspect, the present invention provides a method for producing a pharmaceutical composition comprising the steps of: - providing a first substrate; - applying to the surface of a first substrate a composition according to the invention to obtain a coated first substrate; - providing a second substrate; - optionally applying to the surface of a second substrate a composition according to the invention to obtain a coated second substrate; and - adhering the first coated substrate to an optionally coated second substrate; The present invention relates to a process for producing a bonded substrate, comprising:

[0094] In a fifth aspect, the present invention relates to an adhesive substrate obtainable by the process described above.

[0095] The definitions and preferred embodiments provided in the context of the first aspect of the invention also apply in the context of the second to fifth aspects of the invention.

[0096] Coating Application of the adhesive formulation can be carried out in known manner, for example by brushing, pouring, knife coating, spraying, rolling or dipping. Drying of the adhesive film can be carried out at room temperature or at elevated temperatures.

[0097] The formulations according to the invention can be used, for example, as adhesives for bonding to target substrates of the same or different type, for example wood, paper, plastics, textiles, leather, rubber, or inorganic materials such as ceramics, metals, stoneware, fiberglass or cement.

[0098] Polychloroprene-based contact adhesives are primarily solvent-borne adhesives that are applied to both parts, bonded, dried, and then joined under pressure to obtain a bond with high strength at room temperature and, after the optional addition of a corresponding high-melting resin, also at high temperatures (heat resistance).

[0099] It can be seen that adhesives that allow such uncomplicated and rapidly carried out gluing processes are of great commercial importance. Polychloroprene adhesives are thus used in all sectors, for example in the shoe or furniture industry, where articles are produced in small numbers or in large numbers in various shapes or sizes according to the individual needs. Similarly, the main sectors of use are, for example, the building industry or shipbuilding, where the gluing process must be carried out on site without the use of complex machines, i.e. in the form of an assembly operation, such as the laying of interior fittings or floor coverings. EXAMPLES

[0100] The following examples further illustrate the present invention but should not be construed as limiting its scope:

[0101] Preparation of the adhesive composition: The adhesive composition was prepared in a direct dissolution process. For this purpose, all of the solid ingredients, apart from the polychloroprene and the ethylene-vinyl acetate copolymer, were placed in a sealable container, the solvent was weighed in, and then the polychloroprene was added. Dissolution was carried out at 23° C. and 1000 rpm using a 4.5 cm dissolver disk.

[0102] Ingredients of the adhesive composition: Baypren 320-2 polychloroprene (rapid crystallization) available from ARLANXEO SFP-121H: Alkylphenol resin available from SI Group Rhenofit D / A: Magnesium oxide (MgO) commercially available from RheinChemie Zinc Oxide, Active: Commercially Available Zinc Oxide (ZnO) from LANXESS Antioxidant: 6PPD (Vulkanox 4020LG) available from Lanxess 2-Methyltetrahydrofuran: Viridisol M (bio-based 2-methyltetrahydrofuran) available from Pennakem Ethyl acetate: Commercially available biobased ethyl acetate from Helm AG n-Hexane, cyclohexane, methylcyclohexane and toluene available from Merck.

[0103] Viscosity measurement: The solution viscosity of the composition is measured with a Brookfield digital rotational viscometer LV DV II+ with spindle LV2 (62) and equipped with guard legs. The composition is conditioned at 23°C and measurements are carried out at 23°C at the highest possible rotation speed. The results of the measurements are reported in mPa. * Denoted by s.

[0104] Open time determination: The open time was measured using a doctor blade with a width of 10 cm and a gap width of 200 μm, DINA4, 160 g / m 2It is determined by applying the composition on a piece of kraft paper. The paper is cut into strips 3 cm wide. Once applied, the solvent begins to evaporate. After a preset time, the adhesive layers on the strips are pressed together. The adhesive is within its open time as long as the glued papers cannot be separated without destroying the paper. The open time is exceeded if the papers can be separated after bonding. The maximum open time of an adhesive is the time difference between the application of the adhesive and the moment when adhesion was last possible.

[0105] result:

[0106] [Table 1]

[0107] [Table 2]

[0108] The compositions according to the present invention have been found to exhibit long open times in combination with high solution viscosity, whereas the compositions according to JP 2003226852 do not exhibit such a combination of advantages.

[0109] Further findings It is understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present invention should not be determined solely with reference to the above description, but also with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. Omission of any aspect of the subject matter disclosed herein in the following claims is not a disclaimer of such subject matter, nor should it be deemed that the inventors did not consider such subject matter to be part of the disclosed inventive subject matter.

[0110] Furthermore, a plurality of elements, components, ingredients, or steps may be provided by a single integrated element, component, ingredient, or step. Alternatively, a single integrated element, component, ingredient, or step may be divided into separate elements, components, ingredients, or steps. The disclosure of "a" or "a type" to describe an element, component, ingredient, or step is not intended to exclude the element, component, ingredient, or step.

[0111] Furthermore, use of the terms "comprising" or "including" to describe an element, component, ingredient, or step herein also contemplates embodiments that consist of or consist essentially of the element, component, ingredient, or step.

[0112] Furthermore, where applicable and unless otherwise specified, references to "%" in the specification are preferably understood to represent "% by weight", more preferably "% by weight, based on the total weight of the composition according to the present invention".

Claims

1. -Polychloroprene; and The first organic solvent is -2-methyltetrahydrofuran; A composition containing the following:

2. The composition according to claim 1, further comprising a second organic solvent which is ethyl acetate.

3. The composition according to claim 1 or 2, wherein the first organic solvent, which is 2-methyltetrahydrofuran, is generated or obtained from corn production waste.

4. - Viscosity exceeding 7000 mPas at a temperature of 23°C, and / or - Open time exceeding 3.5 hours, The composition according to claim 1, which shows the following.

5. The composition according to claim 1, comprising or including polychloroprene and a solvent component comprising a first organic solvent, 2-methyltetrahydrofuran, in an amount of 5 to 100% by weight relative to the total weight of the solvent component.

6. The following steps: (a) A step of providing polychloroprene; (b) - In a bio-based form, and / or - From non-fossil resources, and / or - From corn production waste, A step of providing at least a portion of 2-methyltetrahydrofuran; (d) A step of mixing the components from steps (a) and (b); A process for producing the composition according to claim 1, including the above.

7. The following steps: (c) - In a bio-based form, and / or - From non-fossil resources, A step of providing at least a portion of ethyl acetate; (d') A step of mixing the components from steps (a), (b), and (c); The process according to claim 6, including the process described in claim 6.

8. Use of the composition according to claim 1 as an adhesive and / or sealant.

9. The use according to claim 8, wherein the composition is configured to bond substrates of the same or different types, and which contain wood, paper, plastic, textiles, leather, rubber, and / or inorganic materials.

10. The following steps: - Step of providing the first substrate; - A step of applying the composition described in claim 1 to the surface of the first substrate to obtain a coated first substrate; - Step of providing the second substrate; - A step of adhering the first coating substrate to the second substrate; A process for manufacturing bonded substrates, including [the specified component].

11. A bonded substrate obtained by the process described in claim 10.