TW201910464A - Ribbon-shaped pressure-sensitive adhesive foamed by micro-balloon - Google Patents

Abstract

A foamed, double-sided adhesive tape with different adhesion properties on each side is to be provided, without the need to use subsequently applied compounds. This is achieved with a web-like adhesive compound foamed with micro-balloons, which contains - a blend of at least one poly(meth)acrylate and at least one synthetic rubber and - a plurality of expandable micro-balloons, and is characterised in that the proportion of micro-balloons on a random volume of the top side formed from a section of the web surface and a depth of 20[mu]m differs by at least 12% from the proportion of micro-balloons on a random volume of the bottom side of the web-like adhesive compound formed from a section of the web surface and a depth of 20[mu]m. The invention also relates to a method for producing an adhesive compound of this kind, and the use of same.

Description

   Band-shaped pressure-sensitive adhesive foamed with micro balloons   

The present invention relates to the technical field of pressure-sensitive adhesives, which are often used to produce temporary or permanent adhesion. Specifically, a tape-shaped pressure-sensitive adhesive having different adhesion-related properties on its upper and lower sides is proposed. The subject matter of this application is also related to a method for manufacturing such a pressure-sensitive adhesive and its use for bonding components of electronic devices.

Foam tape is often used when bonding substrates with tape. On the one hand, it can reduce weight and save costs by reducing the density of the pressure-sensitive adhesive; on the other hand, it can impart special properties, such as improved shock resistance, improved compression modulus, and / or higher adhesive rigidity. However, foamed adhesives or tapes generally have rougher surfaces than their unfoamed counterparts, and they are also harder and therefore less capable of wetting the surface of the substrate. This results in slower application, which prevents the bond from withstanding high stresses at first. To compensate for these shortcomings, but still benefit from favorable foam characteristics, foam tapes are often equipped with so-called post-coating materials and are therefore provided as two- or three-layer articles.

In order to firmly bond different substrates, it is also desirable to provide a foam double-sided tape with different adhesive properties on the upper and lower sides. For this purpose as well, a material suitable for each substrate to be adhered is provided before coating the material.

However, the production of foamed adhesive tape with coated materials is obviously more complicated than single-layer products, and it is usually linked to higher costs, for example, to ensure sufficient interlayer adhesion between layers. For this purpose, in many cases surface treatment must be performed by corona or other physical or chemical methods before the layers are bonded to each other.

The object of EP 2 062 951 A1 is a three-layer adhesive tape with an optionally foamed viscoelastic carrier layer. The carrier layer and the post-coating material are both based on poly (meth) acrylate.

The object of EP 1 995 282 A1 is a multilayer tape with a similar structure.

The foaming of a specific layer of the tape can basically be introduced as a compressed gas or a propellant (such as nitrogen or CO ₂ ) released by a chemical reaction in the adhesive or a foaming agent (such as glass, ceramic Or polymer formed hollow spheres). It is often desirable to have a controlled foam that leads to predictable and controllable foam properties. For this reason, it has been confirmed that it is better to introduce as a hollow body, thereby realizing closed-cell composite microsphere foam. The use of hollow bodies has proven to be preferred.

A "micro balloon" is understood to be a flexible, hollow hollow sphere that expands in its ground state and has a thermoplastic polymer shell. This ball is filled with a low boiling point liquid or a liquefied gas. As the housing material, polyacrylonitrile, PVDC, PVC or polyacrylate is used in particular. As a low-boiling point liquid, it is particularly suitable for hydrocarbons or lower alkanes, such as isobutane or isopentane, which are sealed as a liquefied gas in a polymer shell under pressure.

By acting on the micro-balloon, especially by heat, the outer polymer shell softens. At the same time, the liquid propellant gas located in the shell is transformed into its gaseous state. In this case the micro balloon expands irreversibly and expands three-dimensionally. The expansion ends when the internal pressure is balanced with the external pressure. Since the polymer shell is retained, closed-cell foam is thus achieved.

Foam-containing products made using expandable microspheres, such as the subject matter of WO 00/06637 A1.

Micro-balloon pressure-sensitive adhesives based on poly (meth) acrylate and synthetic rubber are the objects of DE 10 2013 215 296 A1 and DE 10 2013 215 297 A1. Similar adhesives for bonding components in optical, electronic or precision mechanical devices are described in DE 10 2014 207 974 A1.

There is a continuing need for high-performance foam tapes suitable for bonding different substrates. Therefore, the subject of the present invention is to provide a double-sided foam tape with different adhesive properties on both sides, and avoid the disadvantages related to the coating material after use. The solution to this problem is based on the idea of improving the properties of both sides by the porosity generated by the expanded micro-balloon.

The first and general object of the present invention is a tape-shaped pressure-sensitive adhesive foamed with micro-balloons, comprising:-a blend composed of at least one poly (meth) acrylate and at least one synthetic rubber, and -A large number of inflatable micro-balloons, characterized in that the proportion of micro-balloons in a volume formed by a portion of an arbitrary tape surface on the upper side of the tape-shaped pressure-sensitive adhesive and a depth of 20 μm is related to an arbitrary tape on the lower side A portion of the surface differs from the proportion of micro-balloons in the volume formed by a depth of 20 μm by at least 12%.

①, ②‧‧‧ Extension lines in the direction of rising (range before step) or falling (range after step) temperature

③, ④‧‧‧are the same area between an extension line, the best fit line and the measurement curve

⑤‧‧‧ is tangent to two extension lines parallel to the ordinate on the step range to form two faces of the same area ③ and ④

FIG. 1 is a temperature recording chart for determining a glass transition temperature.

The pressure-sensitive adhesive according to the present invention is a single-layer adhesive tape having the characteristics of a double-layer adhesive tape. It has different adhesion values on its upper and lower sides, so it can meet the special requirements for bonding different substrates. Because this is achieved in a single adhesive, the disadvantages of coating materials after application are avoided. In addition, other preferable properties can be satisfied, which will be further explained below.

A two-layer pressure-sensitive adhesive according to the present invention can be obtained by laminating two band-shaped pressure-sensitive adhesives according to the present invention according to the structure ABBA or BAAB, which has the characteristics of a symmetrical three-layer product, but only one pretreatment step is required for this Produces good interlayer adhesion, rather than two of traditional products and methods.

A pressure-sensitive adhesive according to the present invention, as commonly used in general spoken language, is understood as a substance that is permanently adhesive and tacky at least at room temperature. The pressure-sensitive adhesive is characterized in that it can be applied to a substrate by pressure and remains attached thereto, wherein the pressure used and the duration of the effect of this pressure are not further defined. However, it usually depends on the exact pressure-sensitive adhesive and the type, temperature and humidity of the substrate. To achieve the adhesion effect, the short-term and minimum pressure (which does not exceed a slight touch for a short time) is sufficient. In other cases, the long-term duration of the effects of high pressure may be required.

Pressure-sensitive adhesives have special characteristics of viscoelastic properties, which lead to permanent adhesion and tackiness. It is characterized in that when it is mechanically deformed, a viscous flow process and an elastic restoring force are formed. The two processes are related to each other in a specific ratio in terms of their respective ratios, which depend on the exact composition, structure, and degree of crosslinking of the pressure-sensitive adhesive, as well as the speed and duration of deformation, and temperature.

Partial viscous flow is necessary to obtain adhesion. Only the sticky part (often produced by a macromolecule with a relatively high mobility) can have good wetting properties and good spreadability to the adhesive substrate. A high proportion of viscous flow results in high pressure sensitive adhesion, also known as initial adhesion or surface adhesion, and therefore often results in high adhesion. Highly crosslinked systems, crystalline polymers or glassy cured polymers lack a flowable part and are usually not pressure sensitive or only slightly pressure sensitive.

Part of the elastic restoring force is necessary to obtain cohesion. It is produced by, for example, extremely long-chain and strongly entangled macromolecules and by macromolecules crosslinked physically or chemically, and allows the forces acting on the adhesion to be transferred. It enables the bond to withstand to a sufficient extent a sustained stress (e.g. in the form of permanent shear stress) acting on it for a longer period of time.

In order to more accurately describe and quantify the size of the elastic and viscous parts and the proportion of these parts relative to each other, the storage modulus (G ') and loss modulus (G ") that can be determined by dynamic mechanical analysis (DMA) are used The size of G 'is the measure of the elastic part, and G "is the measure of the sticky part of the substance. Both depend on the deformation frequency and temperature.

This size can be determined by means of a rheometer. The material under test is subjected to a shear stress of sinusoidal oscillations in a plate / plate configuration, for example. In a shear stress controlled device, deformation is measured as a function of time and the time shift of this deformation to the input shear stress. This time shift is called the phase angle δ.

The storage modulus is defined as follows: G '= (τ / γ) ‧cos (δ) (τ = shear stress, γ = deformation, δ = phase angle = phase shift between shear stress vector and deformation vector). The loss modulus G "is defined as: G" = (τ / γ) ‧sin (δ) (τ = shear stress, γ = deformation, δ = phase angle = phase shift between the shear stress vector and the deformation vector ).

When the 23 ℃ to 10 ^° to 10 ¹ rad / G 'and G of the frequency range modification sec "at least partially in the range 10 ³ to 10 ⁷ Pa, the particular substance is considered to be the pressure-sensitive adhesive properties, and in least a period of the present invention are the respective window is defined in particular a pressure-sensitive adhesive property. "part" means G 'curve and at least one segment within the window G "curve, which comprises a window system comprising 10 to ¹⁰⁰ A deformation frequency range (abscissa) of ¹ rad / sec and a G 'value range (ordinate) from 10 ³ to 10 ⁷ Pa are generated.

"Poly (meth) acrylate" is understood to be a polymer which is obtained by free-radical polymerization of acrylic monomers and / or methacrylic monomers and other copolymerizable monomers as required. "Poly (meth) acrylate" is to be understood in particular as a polymer having a monomer matrix of at least 50% by weight consisting of acrylic acid, methacrylic acid, acrylates and / or methacrylates, based on related polymerization The entire monomer matrix of the product at least partially comprises acrylate and / or methacrylate, preferably at least 30% by weight.

The pressure-sensitive adhesive according to the present invention is preferably a poly (meth) acrylate in a total amount of 40 to 70% by weight, and more preferably a total of 45 to 60% by weight, based on the total weight of the pressure-sensitive adhesive. It may contain a single poly (meth) acrylate or multiple poly (meth) acrylates.

The glass transition temperature of the poly (meth) acrylate of the pressure-sensitive adhesive according to the present invention is preferably <0 ° C, more preferably between -20 and -50 ° C. The glass transition temperature of a polymer or the glass transition temperature of a polymer block in a block copolymer is determined according to the present invention by a differential scanning calorimetry (DSC). For this purpose, an untreated polymer sample of about 5 mg was weighed in a small aluminum crucible (capacity 25 μl) and sealed with a perforated lid. For the measurement system, DSC 204 F1 from Netzsch was used. It is operated under nitrogen for inertization. The sample was cooled to -150 ° C, then heated to + 150 ° C at a heating rate of 10K / min, and then re-cooled to -150 ° C. The next second heating curve was performed again at 10 K / min, and the change in heat capacity was recorded. Glass transitions are identified as steps in the thermogram.

The glass transition temperature is obtained as follows (see Figure 1): the area where the measurement curve extends linearly before and after the step is extended in the direction of rising (range before the step) temperature or falling (range after the step) temperature ( Extension cables ① and ②). Draw a best fit line at the step range parallel to the ordinate tangent to the two extension lines, thus forming two faces of the same area ③ and ④ (one extension line, best fit line and measurement curve respectively between). The junction between the best-fit line and the measurement curve thus positioned is the glass transition temperature.

The poly (meth) acrylate of the pressure-sensitive adhesive according to the present invention preferably contains at least one partially copolymerized functional monomer, particularly preferably a reactive monomer that forms a covalent bond with an epoxy group. The partially copolymerized functional monomer is particularly preferably a reactive monomer that forms a covalent bond with an epoxy group, and more particularly preferably contains at least one functional group selected from the group consisting of a carboxylic acid group. , A sulfonic acid group, a phosphonic acid group, a hydroxyl group, an acid anhydride group, an epoxy group, and an amine group; in particular, it contains at least one carboxylic acid group. Most preferably, the poly (meth) acrylate portion of the pressure-sensitive adhesive according to the present invention comprises copolymerized acrylic acid and / or methacrylic acid. All of the aforementioned groups are reactive with epoxy groups, whereby the poly (meth) acrylate can be preferably thermally crosslinked with the added epoxide.

The poly (meth) acrylate of the pressure-sensitive adhesive according to the present invention may preferably be derived from the following monomer constituents: a) at least one acrylate and / or methacrylate of the formula (1) CH ₂ = C (R ^I ) (COOR ^II ) (1), where R ^I = H or CH ₃ , and R ^II is an alkyl group having 4 to 18 carbon atoms; b) at least one ethylenically unsaturated monomer having At least one selected functional group selected from the group consisting of carboxylic acid group, sulfonic acid group, phosphonic acid group, hydroxyl group, acid anhydride group, epoxy group and amine group; c) optional other acrylates and / Or methacrylate and / or ethylenically unsaturated monomer, which can be copolymerized with component (a).

Particularly preferred is the monomer of component a) selected at a ratio of 45 to 99% by weight, the monomer of component b) selected at a ratio of 1 to 15% by weight, and the monomer of component c) selected at a ratio of 0 to 40% by weight Where the data is based on the monomer mixture for the base polymer without any additives (such as resins).

The monomers of component a) are generally softened, relatively non-polar monomers. It is particularly preferred that R ^II of monomer a) is an alkyl group having 4 to 10 carbon atoms or is 2-propylheptyl acrylate or 2-propylheptyl methacrylate. The monomer of formula (1) is selected in particular from the group consisting of: n-butyl acrylate, n-butyl methacrylate, n-amyl acrylate, n-amyl methacrylate, n-amyl acrylate, N-hexyl acrylate, n-hexyl methacrylate, n-heptyl acrylate, n-octyl acrylate, n-octyl methacrylate, n-nonyl acrylate, isobutyl acrylate, isooctyl acrylate, isooctyl methacrylate, acrylic acid 2-ethylhexyl, 2-ethylhexyl methacrylate, 2-propylheptyl acrylate and 2-propylheptyl methacrylate.

The monomer of component b) is particularly preferably selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, Dimethacrylic acid, β-propenyloxypropionic acid, trichloroacrylic acid, vinylacetic acid, vinylphosphonic acid, maleic anhydride, hydroxyethyl acrylate (especially 2-hydroxyethyl acrylate), hydroxyacrylic acid Propyl (especially 3-hydroxypropyl acrylate), hydroxybutyl acrylate (especially 4-hydroxybutyl acrylate), hydroxyhexyl acrylate (especially 6-hydroxyhexyl acrylate), hydroxyethyl methacrylate ( In particular, hydroxy 2-hydroxyethyl methacrylate), hydroxypropyl methacrylate (especially 3-hydroxypropyl methacrylate), hydroxybutyl methacrylate (especially 4-hydroxybutyl acrylate), Hydroxyhexyl acrylate (especially 6-hydroxyhexyl methacrylate), allyl alcohol, propylene acrylate, propylene methacrylate.

The monomers of component c) include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate, benzyl acrylate, benzyl methacrylate, and secondary butyl acrylate. , Tertiary butyl acrylate, phenyl acrylate, phenyl methacrylate, isopropyl acrylate, isopropyl methacrylate, tertiary butyl phenyl acrylate, tertiary butyl methacrylate, methacrylic acid Dodecyl acrylate, isodecyl acrylate, n-dodecyl acrylate, n-undecyl acrylate, n-octadecyl acrylate, tridecyl acrylate, n-aracosyl acrylate, cyclohexyl methacrylate, methacrylic acid ring Amyl ester, phenoxyethyl acrylate, phenoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2-butoxyethyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, acrylic acid 3,5-dimethyladamantyl ester, 4-cumyl phenyl methacrylate, cyanoethyl acrylate, cyanoethyl methacrylate, 4-biphenyl acrylate, 4-biphenyl methacrylate , 2-naphthyl acrylate, 2-naphthyl methacrylate, tetrahydrofuran acrylate Diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, 3-methoxymethyl acrylate, 3-methoxy acrylate Butyl butyl, 2-phenoxyethyl methacrylate, diethylene glycol monobutyl ether methacrylate, ethylene glycol acrylate, ethylene glycol monomethacrylate, polyethylene glycol monomethyl ether methylate Acrylate 350, polypropylene glycol monomethyl ether methacrylate 500, propylene glycol monomethacrylate, diethylene glycol monobutyl ether methacrylate, triethylene glycol monoethyl ether methacrylate, octafluoroacrylate Amyl ester, octafluoropentyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 1,1,1,3,3,3-hexafluoroisopropyl acrylate, 1,1 methacrylate , 1,3,3,3-hexafluoroisopropyl ester, 2,2,3,3,3-pentafluoropropyl methacrylate, 2,2,3,4,4,4-hexafluoro methacrylate Butyl ester, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, methacrylic acid 2, 2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyl ester, dimethylaminopropylacrylamide, dimethylaminepropylmethyl Acrylic , N- (1-methylundecyl) acrylamide, N- (n-butoxymethyl) acrylamide, N- (butoxymethyl) methacrylamide, N- (ethoxy) Methyl) acrylamide, N- (n-octadecyl) acrylamide; N, N-dialkyl substituted amines, such as N, N-dimethylacrylamide and N, N-dimethyl Methacrylamide; N-benzylmethacrylamine, N-isopropylacrylamide Amine, N-methylolmethacrylamide, acrylonitrile, methacrylonitrile; vinyl ethers, such as vinyl methyl ether, ethyl vinyl ether, vinyl isobutyl ether; vinyl esters, Such as vinyl acetate; vinyl halides, vinylidene halides, vinylpyridines, 4-vinylpyridines, N-vinylphthalimidine imine, N-vinyllactam, N-vinyl pyrrolidone, styrene , Α- and p-methylstyrene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene, 3,4-dimethoxystyrene; macromonomers, such as Poly 2-methacrylate (weight average molecular weight Mw (determined by GPC) from 4000 to 13000 g / mol), poly (methyl propylene Methyl enoate) ethyl methacrylate (Mw is 2000 to 8000 g / mol).

The monomer of component c) is preferably selected from monomers containing functional groups that support the subsequent radiation chemical crosslinking (for example, by electron beam, UV). Suitable copolymerizable light initiators are, for example, benzoin acrylate and acrylate-functionalized diphenyl ketone derivatives. Monomers that support cross-linking by irradiation with an electron beam are, for example, tetrahydrofuran acrylate, N-tertiary butylacrylamide and allyl acrylate.

The preparation of the poly (meth) acrylate is preferably accomplished by conventional radical polymerization or controlled radical polymerization. Poly (meth) acrylates can be made by copolymerization of monomers under the use of general polymerization initiators and optional regulators, which are in the bulk at ordinary temperatures, in emulsions (such as in water Or liquid hydrocarbons), or in solution.

The poly (meth) acrylate is preferably copolymerized in a solvent by a monomer, and particularly preferably in a solvent having a boiling point in the range of 50 to 150 ° C, preferably 60 to 120 ° C, based on the total amount of the monomer. It is produced by using a polymerization initiator of 0.01 to 5% by weight, especially 0.1 to 2% by weight.

All general starters are suitable in principle. Examples of free radical sources are: peroxides, hydroperoxides and azo compounds, such as dibenzoylperoxide, cumene hydroperoxide, cyclohexanone peroxide, di (tertiary butyl peroxide) ), Acetamidine cyclohexane persulfonic acid, diisopropyl peroxydicarbonate, tert-butyl peroctoate and tetraphenyl-1,2-ethylene glycol. Preferred free radical initiators are 2,2'-azo (2-methylbutyronitrile) (Vazo® 67 ^{TM from} DuPont) or 2,2'-azobis (2-methylpropionitrile) (2,2'-azobisisobutyronitrile;AIBN; Vazo® 64 ^{™ from} Dupont).

For the manufacture of poly (meth) acrylates, the preferred solvents are: alcohols such as methanol, ethanol, n-propanol and isopropanol, n-butanol and isobutanol, especially isopropanol and / or isopropanol Butanol; hydrocarbons, such as toluene and petroleum ethers with a boiling point in the range of 60 to 120 ° C; ketones, especially acetone, methyl ethyl ketone, methyl isobutyl ketone; esters, such as ethyl acetate, and a mixture of the above solvents liquid. A particularly preferred solvent is a mixed liquid containing isopropyl alcohol in an amount of 2 to 15% by weight, especially 3 to 10% by weight, based on the solvent mixture used.

The poly (meth) acrylate is preferably concentrated after the production (polymerization) of the poly (meth) acrylate, and the further processing of the poly (meth) acrylate is carried out substantially without a solvent. Concentration of the polymerization product can be accomplished without the crosslinker substance and the accelerator substance. However, it is also possible that these compound classes are added to the polymerization product before being concentrated, and then concentrated in the presence of these substances.

The polymerization product can be transferred to a kneader after the concentration step. If necessary, concentration and kneading can also be performed in the same reactor.

The weight average molecular weight M _{w of the} polyacrylate is preferably in the range of 20,000 to 2,000,000 g / mol; particularly preferably in the range of 100,000 to 1,500,000 g / mol, and most preferably in the range of 150,000 to 1,000,000 g / mol. For this reason, it is preferred to perform polymerization in the presence of a suitable polymerization regulator, such as a thiol, a halogen compound, and / or an alcohol, to adjust the desired average molecular weight.

The data of the number average molecular weight M _n and the weight average molecular weight M _w in this specification are measured with reference to known gel permeation chromatography (GPC). The measurement was performed on 100 μl of a clear filtered sample (sample concentration of 4 g / l). As the eluent, tetrahydrofuran having trifluoroacetic acid of 0.1% by volume was used. The measurement was performed at 25 ° C.

As the protective column system, use the column model PSS-SDV, 5μm, 10 ³ Å, 8.0mm * 50mm (the data here and below are in the following order: model, particle size, porosity, inner diameter * length; 1Å = 10 ^-10 m). The separation system uses a combination of the following types of columns: PSS-SDV, 5μm, 10 ³ Å, and 10 ⁵ Å and 10 ⁶ Å, all with 8.0mm * 300mm (Polymer Standards Service company's column; by using a differential refractor) (Shodex RI71). The flow rate is 1.0 ml per minute. In the case of polyacrylate, calibration is performed on a PMMA standard (polymethyl methacrylate calibration), and other (resin, elastomer) is performed on a PS standard (polystyrene calibration).

The poly (meth) acrylate preferably has a K value of 30 to 90, particularly preferably 40 to 70, measured in toluene (1% solution, 21 ° C). According to Fikentscher, the K value is a good measure of the molecular weight and viscosity of the polymer.

The principle of this method is based on the capillary viscosity determination of the relative solution viscosity. To this end, the test substance was dissolved by shaking in toluene for three minutes to obtain a 1% solution. The relative viscosity of the sample solution was determined by measuring the flow time in a Vogel-Ossag viscometer at 25 ° C and referring to the viscosity of the pure solvent. The K value can be read from the table in accordance with Fikentscher [P.E. Hinkamp, Polymer, 1967, 8, 381] (K = 1000k).

The poly (meth) acrylate according to the present invention preferably has a polydispersity PD <4 and therefore has a relatively narrow molecular weight distribution. Although the material based on it has relatively low molecular weight after cross-linking, it has particularly good shear strength. In addition, the lower polydispersity can be processed more easily from the melt, as compared to the more widely distributed poly (meth) acrylates, with substantially the same application characteristics, the flow viscosity is lower. Poly (meth) acrylates with a narrow distribution can preferably be produced by anionic polymerization or by a controlled radical polymerization process, the latter being particularly suitable. The corresponding poly (meth) acrylate can also be produced through N-oxyl. In addition, atom transfer radical polymerization (ATRP) can be started in a preferred manner to synthesize narrow poly (meth) acrylates. Among them, monofunctional or bifunctional secondary or tertiary halogenation is preferably used as a starter. Cu-, Ni-, Fe-, Pd-, Pt-, Ru-, Os-, Rh-, Co-, Ir-, Ag- or Au- complexes for extraction of halides. RAFT polymerization is also suitable.

The poly (meth) acrylate of the pressure-sensitive adhesive according to the present invention is preferably a thermal crosslinking agent through a crosslinking reaction due to the functional groups contained therein (especially in the sense of addition reaction or substitution reaction). Cross-linking. All thermal cross-linking agents can be used that:-ensure a long processing time so that gelation does not occur during the processing process, especially the extrusion process,-at temperatures lower than the processing temperature, especially It is at room temperature that the polymer is rapidly post-crosslinked to the desired degree of crosslinking.

As the cross-linking agent, for example, a polymer containing a carboxyl group, an amine group, and / or a hydroxyl group and an isocyanate (particularly, an aliphatic or blocked isocyanate (for example, an amine-deactivated trimerized isocyanate)) Composition of the combination. Suitable isocyanates are in particular MDI [4,4-methylenebis (phenyl isocyanate)], HDI [hexamethylene diisocyanate, 1,6-hexyl diisocyanate] and / or IPDI [isophorone diisocyanate , 5-isocyanato-1-isocyanatomethyl-1,3,3-trimethylcyclohexane] trimer derivatives, such as Desmodur® N3600 and XP2410 (both BAYER) AG: aliphatic polyisocyanate, low viscosity HDI-trimer). Also suitable are surface-deactivated dispersions of micronized trimeric IPDI BUEJ 339® (now HF9® (BAYER AG)).

Based on the total amount of polymers to be crosslinked, it is preferred to use from 0.1 to 5% by weight of a crosslinking agent, especially from 0.2 to 1% by weight.

It can also be crosslinked by a complexing agent (also called a chelating agent). A preferred complexing agent is, for example, aluminum acetoacetone.

The poly (meth) acrylate, which is preferably a pressure-sensitive adhesive according to the present invention, is crosslinked by an epoxide or by one or more epoxy-containing substances. The epoxy-containing substance is especially a polyepoxide, that is, it has at least two epoxy groups; its overall effect accordingly generates a poly (meth) acrylate functional group-bearing unit linkage. The epoxy-containing substance may be an aromatic compound or an aliphatic compound.

Very suitable polyepoxides are: oligomers of epichlorohydrin, polyhydric alcohols (especially ethylene glycol, propylene glycol and butanediol, polyethylene glycol, diethanol sulfide, glycerol, neopentyl alcohol , Sorbitol, polyvinyl alcohol, polyallyl alcohol, etc.), epoxy ethers, polyphenols [especially resorcinol, hydroquinone, bis (4-hydroxyphenyl) methane, bis (4-hydroxy- 3-methylphenyl) methane, bis (4-hydroxy-3,5-dibromophenyl) methane, bis (4-hydroxy-3,5-difluorophenyl) methane, 1,1-bis (4 -Hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy -3-chlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) -propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) -Propane, bis (4-hydroxyphenyl) -phenylmethane, bis (4-hydroxyphenyl) -phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) -4'-methylphenylmethane, 1,1-bis (4-hydroxyphenyl) -2,2,2-trichloroethane, bis (4-hydroxyphenyl)-(4-chlorophenyl) Methane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) cyclohexylmethane, 4,4'-dihydroxydiphenyl, 2,2'-di Hydroxydiphenyl, 4,4'-dihydroxydiphenyl hydrazone] epoxy ether and its hydroxyethyl ether; phenol-formaldehyde condensation products, such as phenol alcohols and phenolic resins; epoxy containing S and N Compounds such as N, N-diglycidylaniline and N, N'-dimethylglycidyl-4,4-diaminodiphenylmethane; and polyunsaturated carboxylic acids in a general manner Or epoxides made from unsaturated carboxylic acid esters of unsaturated alcohols; glycidyl esters; polyglycidyl esters, which can be polymerized or copolymerized by glycidyl esters of unsaturated acids It can be obtained, or can be obtained from other acidic compounds, for example, from cyanuric acid, diglycidyl sulfide or cyclized trimethylenetrifluorene or a derivative thereof.

Very suitable ethers such as: 1,4-butanediol diglycidyl ether, polypropylene glycol-3-glycidyl ether, cyclohexanedimethanol diglycidyl ether, glycerol triepoxy Propyl ether, neopentyl glycol diglycidyl ether, neopentyl tetraol tetraglycidyl ether, 1,6-hexanediol diglycidyl ether, polypropylene glycol diglycidyl ether, three Hydroxypropane triglycidyl ether, neopentaerythritol tetraglycidyl ether, bisphenol A diglycidyl ether and bisphenol F diglycidyl ether.

Other preferred epoxides are cycloaliphatic epoxides, such as 3,4-epoxycyclohexanoic acid-3,4-epoxycyclohexyl methyl ester (UVACure1500).

Particularly preferred is that the poly (meth) acrylate is cross-linked by a cross-linking agent / accelerator system ("cross-linking system") for better control of processing time, cross-linking kinetics, and degree of cross-linking. The cross-linking agent / accelerator system preferably contains at least one epoxy-containing substance as a cross-linking agent, with at least one polymer having a temperature lower than the melting temperature of the polymer to be cross-linked used in the crosslinking reaction by An oxy compound is a substance that exerts an acceleration effect as an accelerator.

As the accelerator, amines are particularly preferred according to the present invention. It is formally understood as a substitution product of ammonia; in the following formula, these substituents are represented by "R", and specifically include: alkyl groups and / or aryl groups. Particularly preferred is the use of amines that will not or will react slightly with the polymer to be crosslinked.

In principle, the accelerator can be selected from: primary amine (NRH ₂ ), secondary amine (NR ₂ H), and tertiary amine (NR ₃ ). Of course, it also includes a plurality of primary amine groups and / or secondary amine groups and / Or tertiary amine group. Very good accelerators are tertiary amines, such as: triethylamine, triethylene glycol, benzyldimethylamine, dimethylaminomethylphenol, 2,4,6-ginseng (N, N-di Methylaminomethyl) phenol, N, N'-bis (3- (dimethylamino) propyl) urea. Other preferred accelerators are polyamines, such as diamines, triamines, and / or tetraamines, such as diethylenetriamine, triethylenetetramine, and trimethylhexamethylenediamine.

Other preferred accelerators are amine alcohols, especially secondary and / or tertiary amine alcohols. In the case where there are multiple amine functional groups in each molecule, at least one is preferred, and all of them are particularly preferred. The amine functionality is secondary and / or tertiary. Particularly preferred such accelerators are: triethanolamine, N, N-bis (2-hydroxypropyl) ethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, 2-aminocyclohexanol, bis ( 2-hydroxycyclohexyl) methylamine, 2- (diisopropylamino) ethanol, 2- (dibutylamino) ethanol, N-butyldiethanolamine, N-butylethanolamine, 2- [bis (2-hydroxy Ethyl) amino] -2- (hydroxymethyl) -1,3-propanediol, 1- [bis (2-hydroxyethyl) amino] -2-propanol, triisopropanolamine, 2- ( Dimethylamino) ethanol, 2- (diethylamino) ethanol, 2- (2-dimethylaminoethoxy) ethanol, N, N, N'-trimethyl-N'-hydroxyethylbis Amine ether, N, N, N'-trimethylamine ethylethanolamine and N, N, N'-trimethylamine propylethanolamine.

Other suitable accelerators are: pyridine, imidazole (such as 2-methylimidazole), and 1,8-diazinebicyclo [5.4.0] -undec-7-ene. Cycloaliphatic polyamines can also be used as accelerators. Also suitable are phosphate-based accelerators, such as phosphine and / or rhenium compounds, such as triphenylphosphine or tetraphenylphosphonium tetraphenylborate.

A quaternary ammonium compound can also be used as an accelerator, for example: tetrabutylammonium hydroxide, cetyltrimethylammonium bromide and alkyldimethylbenzylammonium chloride.

The pressure-sensitive adhesive according to the present invention further includes at least one synthetic rubber.

It is preferably a pressure-sensitive adhesive, and contains a total of 15 to 50% by weight of a synthetic rubber based on the total weight of the pressure-sensitive adhesive, and more preferably a total of 20 to 40% by weight. One or more synthetic rubbers may be contained in the pressure-sensitive adhesive according to the present invention.

Preferably, the synthetic rubber of the pressure-sensitive adhesive according to the present invention is a block copolymer having an AB, ABA, (AB) _n , (AB) _n X, or (ABA) _n X structure, wherein-the blocks A are independent of each other. Represents a polymer formed by polymerizing at least one vinyl aromatic hydrocarbon;-block B each independently represents a polymer formed by polymerizing a conjugated diene and / or isobutylene having 4 to 18 carbon atoms, or Represents a partially or fully hydrogenated derivative of this polymer;-X represents the residue of a coupling agent or initiator, and-n represents An integer of two.

All the synthetic rubbers of the pressure-sensitive adhesive according to the present invention are particularly block copolymers having a structure as shown above. The pressure-sensitive adhesive according to the present invention can therefore also contain a mixture of various block copolymers having a structure as described above.

A preferred synthetic rubber (which is also referred to as a vinyl aromatic block copolymer) contains more than one rubbery block B (soft block) and more than one glassy block A (hard block). Particularly preferred is that the synthetic rubber of the pressure-sensitive adhesive according to the present invention is a block copolymer having a structure AB, ABA, (AB) ₃ X or (AB) ₄ X, in which A, B and X apply the foregoing meanings. More particularly, all the synthetic rubbers of the pressure-sensitive adhesive according to the present invention are block copolymers having a structure AB, ABA, (AB) ₃ X or (AB) ₄ X, wherein A, B and X apply the foregoing meanings. The synthetic rubber of the pressure-sensitive adhesive according to the present invention is particularly a mixture composed of block copolymers having a structure AB, ABA, (AB) ₃ X or (AB) ₄ X, which preferably includes at least diblock copolymerization. Polymer AB and / or triblock copolymer ABA.

Block A is particularly a glassy block having a glass transition temperature (Tg, DSC) preferably above room temperature. Particularly preferred is a glass block having a Tg of at least 40 ° C, particularly at least 60 ° C, more preferably at least 80 ° C, and most preferably at least 100 ° C. The proportion of the vinyl aromatic hydrocarbon block A in the entire block copolymer is preferably 10 to 40% by weight, and particularly preferably 20 to 33% by weight. The vinyl aromatic hydrocarbon used to construct the block A preferably includes styrene and α-methylstyrene. Block A can exist as a homopolymer or copolymer. Particularly preferred is block A is polystyrene.

The block B is particularly a rubbery block or a soft block, which preferably has a Tg below room temperature. The Tg of the soft block is particularly preferably lower than 0 ° C, particularly lower than -10 ° C, such as lower than -40 ° C, and even more preferably lower than -60 ° C.

The preferred conjugated diene as a monomer for the soft block B is specifically selected from the group consisting of butadiene, isoprene, ethylbutadiene, and phenylbutadiene. , Isoprene, pentadiene, hexadiene, ethylhexadiene, dimethylbutadiene and bacteriolene isomers, and any mixture of these monomers. Block B can exist as a homopolymer or a copolymer.

Particularly preferred is a conjugated diene system selected as a monomer for the soft block B from butadiene and isoprene. For example, the soft block B is polyisoprene, polybutadiene, or a partially or completely hydrogenated derivative of these two polymers, especially such as polybutene butadiene; or it includes butadiene and isoprene A polymer composed of a mixture of dienes. More particularly preferred is block B-based polybutadiene.

Preferably, the synthetic rubber in the pressure-sensitive adhesive according to the present invention is dispersed in poly (meth) acrylate. Therefore, the poly (meth) acrylate and the synthetic rubber are preferably both homogeneous phases. The poly (meth) acrylate and the synthetic rubber contained in the pressure-sensitive adhesive are preferably selected so that they cannot be mixed with each other to be homogeneous at 23 ° C. Therefore, the pressure-sensitive adhesive according to the present invention exists in at least two phases at least under a microscope and at least at room temperature. Particularly preferred is that poly (meth) acrylate and synthetic rubber cannot be mixed uniformly with each other in a temperature range of 0 ° C to 50 ° C, especially in a range of -30 ° C to 80 ° C, so that the pressure-sensitive adhesive in these temperature ranges is at least under a microscope There are at least two phases.

When at least two stable phases (one phase is rich in one component and the second phase is rich in another component) can be formed physically and / or chemically, at least under a microscope, even after homogeneous mixing, then these components It is defined in this specification as "not uniformly mixable with each other." A negligibly small amount of one component present in the other (which does not prevent the formation of multiphase) is considered insignificant. That is, there may be a small amount of synthetic rubber in the poly (meth) acrylate phase, and / or a small amount of poly (meth) acrylate component in the synthetic rubber phase, as long as it does not affect the phase separation Just a lot.

Phase separation can be achieved in particular by the presence of discrete regions ("domains") in a continuous matrix, where the discrete regions are rich in synthetic rubber (that is, essentially composed of synthetic rubber), and the continuous matrix It is rich in poly (meth) acrylate (that is, it is substantially composed of poly (meth) acrylate). A suitable analysis system for phase separation is, for example, a scanning electron microscope. However, phase separation can also be identified by, for example, the following methods: Different phase-to-difference scanning calorimetry (DDK, DSC) or dynamic mechanical analysis (DMA) have two independent glass transition temperatures. When it can be clearly shown by at least one analysis method, phase separation is present according to the invention.

In addition, in the local area rich in synthetic rubber, there may be additional multiphases as microstructures, in which the A block forms a phase and the B block forms a second phase.

According to the pressure-sensitive adhesive of the present invention, based on the total weight of the pressure-sensitive adhesive, it preferably contains 40 to 70% by weight of at least one poly (meth) acrylate and 15-50% by weight of at least one synthetic rubber.

"Expandable micro-balloons" are understood as micro-balloons that have not yet been fully inflated, and micro-balloons that have partially inflated but can be further inflated.

According to the present invention, the proportion of micro-balloons in a volume formed by a part of an arbitrary tape surface on the upper side of the tape-shaped pressure-sensitive adhesive and a depth of 20 μm is formed by a part of an arbitrary tape surface on the lower side and a depth of 20 μm. The proportions of micro-balloons in the volume differ by at least 12%. As shown in the test of the present invention, between the upper and lower sides of the tape-shaped pressure-sensitive adhesive according to the present invention, in the case where there is such a difference in the volume ratio of the microballoon, the pressure-sensitive adhesive Different adhesion properties were obtained on both sides. In particular, different adhesive strengths are obtained under short sticking time. Although the difference in adhesion between the two sides decreases over time, it is still noticeable even after the adhesive is fully applied. This allows the side with lower immediate adhesion, as it is often desired, in many applications to have an initial repositioning capability to correct one or more times the tape that may have adhered to the item to be adhered after the initial adhesion. s position. After finding the correct position, the adhesive forces on the next two sides can approach each other, and finally reach the overall stable and load-bearing adhesion.

It is preferable that the proportion of the micro-balloons in the volume formed by a part of an arbitrary tape surface on the upper side of the tape-shaped pressure-sensitive adhesive and a depth of 20 μm is formed by a part of an arbitrary tape surface on the lower side and a depth of 20 μm. The proportion of micro-balloons in the volume differs by at least 15%. It is also preferable that the proportion of the micro-balloons in the volume formed by a part of an arbitrary tape surface on the upper side of the tape-shaped pressure-sensitive adhesive and a depth of 20 μm is formed with a part of an arbitrary tape surface on the lower side and a depth of 20 μm The proportion of micro-balloons in the volume varies by up to 30%, especially up to 24%. It turns out that a particularly stable adhesion can be achieved with the corresponding pressure-sensitive adhesive according to the invention.

The proportion of micro-balloons in a given volume of the pressure-sensitive adhesive according to the present invention is determined by computer tomography (CT) according to the present invention. In particular, it operates with high-resolution X-ray microtomography. Computed tomography can clearly distinguish between gas (cavities created by micro-balloons) and solids (adhesive matrix). In addition, it can have excellent image display. By evaluating with appropriate analysis software and visualization software, it is possible to accurately determine the volume ratio of the micro balloon in the volume under consideration. The specific device parameters are described in the experimental section.

The pressure-sensitive adhesive according to the present invention preferably includes at least one tackifier compatible with poly (meth) acrylate, which may also be referred to as an adhesion enhancer or a tackifier resin. "Tackifier" corresponds to the general knowledge of those skilled in the art, and is understood as a resin of oligomer or polymer, which improves the pressure compared to pressure-sensitive adhesives that are the same except that they do not contain a tackifier. Self-adhesiveness (sensitivity to adhesion, inherent viscosity) of sensitive adhesives.

"Poly (meth) acrylate compatible tackifier" is understood as a tackifier, which compared to pure poly (meth) acrylate The glass transition temperature of the system obtained after the adhesives are thoroughly mixed, although a mixture of poly (meth) acrylate and a tackifier can be used to specify only one Tg. A tackifier that is incompatible with poly (meth) acrylates will cause two Tgs in the system obtained after the poly (meth) acrylate and tackifier are thoroughly mixed, one of which belongs to the poly (meth) acrylate. Meth) acrylate, while the other belongs to a local area of the resin. The determination of Tg in this paper is carried out by DSC (Differential Scanning Calorimetry) calorimetry.

Poly (meth) acrylate-compatible resins preferably have a DACP value below 0 ° C, particularly preferably up to -20 ° C, and / or preferably have a MMAP value below 40 ° C, particularly preferably up to 20 ℃. The measurement of DACP value and MMAP value refer to C. Donker, PSTC Annual Technical Seminar, Proceedings, pages 149 ~ 164, May 2001.

Particularly preferred are terpene novolac resins or rosin derivatives, especially terpene novolac resins, which are compatible with poly (meth) acrylates. The pressure-sensitive adhesive according to the present invention may also include a mixture of a plurality of tackifying resins. The rosin derivative is preferably a rosin ester.

The pressure-sensitive adhesive according to the present invention is preferably based on the total weight of the pressure-sensitive adhesive, and preferably contains a total of 7 to 25% by weight of a poly (meth) acrylate-compatible tackifier, particularly preferably a total of 12 to 20% by weight.

Preferably, the tackifier compatible with poly (meth) acrylate is also compatible with, or at least partially compatible with, synthetic rubber, especially with its soft block B, where the term "compatible" applies correspondingly to the foregoing definition. Polymer / resin compatibility depends in particular on the molecular weight of the polymer or resin. Compatibility is better when the molecular weight is lower. For a given polymer, it may be that low molecular weight components in the molecular weight distribution of the resin are compatible with the polymer and high molecular weight components are incompatible. This is an example of partial compatibility.

The weight of the poly (meth) acrylate to the synthetic rubber in the pressure-sensitive adhesive according to the present invention is preferably from 1: 1 to 3: 1, especially from 1.8: 1 to 2.2: 1.

In the pressure-sensitive adhesive according to the present invention, the weight of the tackifier compatible with poly (meth) acrylate to synthetic rubber is relatively good at a maximum of 2: 1, especially at a maximum of 1: 1. This weight is preferably at least 1: 4.

Particularly preferred is a pressure-sensitive adhesive according to the present invention, based on the total weight of the pressure-sensitive adhesive, including: a) at least one poly (meth) acrylate at 50 to 60% by weight; b) at least 20 to 40% by weight A synthetic rubber; and c) at least one tackifier compatible with the poly (meth) acrylate at 7 to 25% by weight.

According to the use range and desired properties of the pressure-sensitive adhesive according to the present invention, each of them may be alone or combined with one or more other additives or ingredients, including other ingredients and / or additives.

Therefore, the pressure-sensitive adhesive according to the present invention may include, for example, powdery and pellet-shaped (especially abrasive and reinforcing) fillers, dyes, and pigments, such as chalk (CaCO ₃ ), titanium dioxide, zinc oxide, and / Or carbon black.

The pressure-sensitive adhesive according to the present invention preferably contains more than one chalk as a filler. The pressure-sensitive adhesive according to the present invention preferably contains a total of up to 20% by weight of chalk. At this ratio, substantial adhesion properties, such as shear strength at room temperature and immediate adhesion to steel and PE, will not change substantially due to the addition of fillers. In addition, different organic fillers can be included.

In addition, the additives suitable for the pressure-sensitive adhesive according to the present invention are independently selected from other additives, including: non-swellable polymer hollow balls, polymer solid balls, glass hollow balls, glass solid balls, ceramic hollow balls, ceramics Solid balls and / or carbon solid balls ("carbon micro balloons").

In addition, the pressure-sensitive adhesive according to the present invention may include: a flame retardant filler such as ammonium polyphosphate; a conductive filler such as conductive carbon black, carbon fiber, and / or silver-coated balls; a thermally conductive material such as boron nitride, Alumina, silicon carbide; ferromagnetic additives such as iron (III) oxide; organic renewable materials such as wood flour; organic and / or inorganic nano particles; fibers, composites, anti-aging agents, light stabilizers and / or ozone resistance Agent.

The pressure-sensitive adhesive according to the present invention optionally contains more than one softener. As the softener, for example, a (meth) acrylate oligomer, a phthalate, a hydrocarbon oil, a cycloadipate, a water-soluble softener, a soft resin, a phosphate or a polyphosphate can be added.

Preferably, the pressure-sensitive adhesive according to the present invention contains silicic acid, particularly preferably precipitated silicic acid, especially precipitated silicic acid modified with dimethyldichlorosilane surface. With this additive, the thermal shear strength of the pressure-sensitive adhesive can be better adjusted.

The pressure-sensitive adhesive according to the present invention may contain, in addition to the previously listed ingredients, more than one poly (meth) acrylate-compatible hydrocarbon resin. Such hydrocarbon resins (which are also tackifiers) preferably include: hydrogenated polymers of dicyclopentadiene; unhydrogenated, partially hydrogenated, selectively hydrogenated, or fully hydrogenated hydrocarbons based on C5, C5 / C9, or C9 monomer streams Resins, and polyterpene resins based on α-pinene and / or ß-pinene and / or δ-pinene. The hydrocarbon resin preferably has a DACP value of at least 0 ° C, particularly preferably at least 20 ° C, and / or preferably has a MMAP value of at least 40 ° C, particularly preferably at least 60 ° C. The measurement of DACP value and MMAP value refer to C. Donker, PSTC Annual Technical Seminar, Proceedings, pages 149 ~ 164, May 2001. The hydrocarbon resin may be contained in the pressure-sensitive adhesive alone, or may be contained in the pressure-sensitive adhesive as a mixture. Particularly preferred hydrocarbon resins are polyterpene resins based on polyterpene resins of α-pinene and / or ß-pinene and / or δ-pinene.

The density of the pressure-sensitive adhesive according to the present invention is preferably 500 to 1000 kg / m ³ , more preferably 600 to 990 kg / m ³ , and particularly 700 to 980 kg / m ³ .

The thickness of the tape-shaped pressure-sensitive adhesive according to the present invention is preferably 50 to 1500 μm, particularly preferably 70 to 1200 μm, especially 100 to 800 μm, such as 150 μm to 500 μm, or 200 μm to 400 μm.

Another object of the present invention is a method for manufacturing a tape-shaped pressure-sensitive adhesive foamed with micro-balloons, comprising: a) preparing a blend comprising at least one poly (meth) acrylate and at least one synthetic rubber And a large number of inflatable micro-balloon pressure-sensitive adhesives; and b) forming the pressure-sensitive adhesive into a belt shape in a calender nip, wherein the pressure-sensitive adhesive is guided through the calender nip in the following manner: A kneaded material is formed before the calender nip, and the temperature of the pressure-sensitive adhesive in the kneaded material exceeds the expansion temperature of the microballoon, and the temperature of the pressure-sensitive adhesive in the kneaded material-exceeds the microballoon expansion temperature, and The temperature of the pressure-sensitive adhesive is at least 5K at the moment after its manufacture.

According to the method of the present invention, a tape-shaped pressure-sensitive adhesive can be manufactured, which has a previously explained difference in the volume ratio of the micro-balloon between its upper side and its lower side, and has the advantages associated therewith. In addition, the extent and nature of this difference can be controlled by targeted setting of specific process parameters, which will be explained further below. It is therefore possible to produce a single-layer adhesive tape having the properties of a multilayer adhesive tape, in which the specific problems of the multilayer adhesive tape, such as problems arising from, for example, the required interlayer adhesion, can be eliminated. In addition, from the article according to the method of the present invention, an adhesive tape having the properties of a three-layer adhesive tape (the upper side and the lower side have the same post-coating material) can be produced in only one lamination step, in which two produced The sides of the tape with the same proportion of micro-balloons are stacked.

The same applies to the poly (meth) acrylates and synthetic rubbers according to the method of the present invention as described in the pressure-sensitive adhesives of the present invention.

The manufacturing method of the tape-shaped pressure-sensitive adhesive according to the present invention is preferably a continuous method.

The manufacture of the pressure-sensitive adhesive is basically not critical until it is formed into a belt shape in the nip of the calender. It only needs to produce a formable adhesive in the calender nip with expandable (that is, completely unexpanded or (expanded) but further expanded) microballoons. Preferably, the production of the pressure-sensitive adhesive is performed from an adhesive melt. In particular, when the pressure-sensitive adhesive is formed into a belt shape, it exists as a melt in the kneaded mixture before the calender nip and in the calender nip itself. If the material used to make the pressure-sensitive adhesive also contains solvent parts, these parts will be removed from the adhesive at the latest in the kneaded material before the calender nip.

The method for manufacturing a pressure-sensitive adhesive may first include concentrating a poly (meth) acrylate solution or dispersion produced from polymer manufacture. The polymerization product can be concentrated in the absence of a crosslinker substance and an accelerator substance. However, it is also possible to add at most one of these substances to the polymerization product before concentrating and then concentrate in the presence of this substance.

The manufacture of the pressure-sensitive adhesive preferably includes kneading equipment and extrusion equipment. If necessary, the concentrated aggregates used in the adhesive may or may not belong to this mixing equipment and extrusion equipment. After passing through the kneading equipment and the extrusion equipment, the pressure-sensitive adhesive is preferably present as a melt. In particular, the pressure-sensitive adhesive exists as a melt when it starts to be formed into a strip shape in a calender nip.

Synthetic rubber can be added together with the resin compatible with poly (meth) acrylate through the solid feeder in the mixer if necessary. Through the side feeder, the poly (meth) acrylate that is concentrated and if necessary melted can be added to the mixer. In a specific embodiment of the method, concentration and kneading can also be performed in the same reactor. Poly (meth) acrylate compatible or other resins can also penetrate the resin melt and side processing at other process positions (such as after adding synthetic rubber and poly (meth) acrylate) if necessary. Machine join.

Other additives and / or softeners can also be added as solids or melts or in batches in combination with other formulation constituents.

Extruders are used as mixers or as components of kneading equipment and extrusion equipment. The polymer in the mixer, whether because it has entered a melt state or is heated to a melt in the mixer, is preferably present as a melt. It is preferred that the polymerization product in the mixer is kept in the melt by heating.

If an accelerator is used for the cross-linking of the poly (meth) acrylate, it is preferably added to the polymerization product near before further processing, especially before coating or other forming. The time window added before coating is particularly in accordance with the useful life, that is, the processing time that does not negatively change the properties of the resulting product in the melt

The cross-linking agent (e.g., epoxide) and, if necessary, the accelerator can also be added before further processing close to the composition, which is preferably in the phase as previously shown for the accelerator. For this reason, it is preferable to add the cross-linking agent and the accelerator at the same position in the process at the same time, and if necessary, add it in the form of an epoxide / accelerator mixture. Basically, it is also possible to exchange the addition time or position of the cross-linking agent and the accelerator in the embodiment shown above, that is, the accelerator can be added before the cross-linking agent substance.

After kneading and applying the completed pressure-sensitive adhesive, the pressure-sensitive adhesive is formed into a belt shape in the calender nip according to the present invention. The coating and calendering machine can be composed of two, three, four or more rolls.

Preferably, at least one roller is provided with a non-sticking roller surface. It is preferable that all rolls of the calender that are in contact with the pressure-sensitive adhesive are equipped with anti-sticking. As the surface of the anti-sticking roller, a steel / ceramic / polysiloxane composite is preferably used. The surface of such rolls is resistant to thermal and mechanical stress.

It has proven to be particularly advantageous when the surface of the roller used has a surface structure that does not have full contact with the adhesive layer to be processed, that is, the contact area (compared to a smooth roller) is small. Structured rolls such as metal anilox rolls are particularly advantageous, such as steel anilox rolls.

Coating can be performed on a temporary support. The temporary carrier is removed during further processing, such as when packing tape, or when using an adhesive layer. The temporary carrier is preferably a release paper. The pressure-sensitive adhesive can also be covered on both sides with a temporary carrier or with a release mounting paper, respectively.

In the method according to the present invention, a large number of micro-balloons are expandable before the adhesive is formed into a band shape at the calender nip. After leaving the extrusion equipment, the current average expansion rate of the micro-balloon is preferably based on the theoretical maximum elongation, preferably 80% at the maximum, 70% at the most preferred, 60% at the maximum, such as 50% at the maximum. It is also possible that a large number of micro-balloons have minimal or no inflation at this point in time.

The pressure-sensitive adhesive according to the present invention passes through the calender nip in such a manner that a kneaded product is formed before the calender nip. The kneaded material preferably has an elongation of 1.0 to 10 cm on a plane orthogonal to the plane extending from the machine direction and the calender nip.

In the present invention, there is a temperature difference of at least 5K between the pressure-sensitive adhesive immediately after its manufacture (for example, after leaving the nozzle) and the pressure-sensitive adhesive kneaded material before the calender nip, wherein The temperature is higher. It is presumed that due to flow conditions, such as turbulent flow, a higher temperature is formed in the kneaded product, which temperature exceeds the expansion temperature of the microballoon according to the present invention. In this way, kneading will continue in the kneaded material, or even certain micro-balloons will begin to expand first. Possibly due to the flow conditions in the kneaded material, this expansion may be performed at different intervals with unequal intensity, and the volume ratio of the micro-balloon is adjusted to the gradient according to the present invention.

The preparation of the pressure-sensitive adhesive preferably includes kneading equipment and extrusion equipment. The temperature of the pressure-sensitive adhesive after leaving the extrusion equipment, for example, after passing through the nozzle, exceeds the expansion temperature of the microballoon, and in the kneaded product. The temperature of the pressure-sensitive adhesive is at least 10K higher than the current temperature of the pressure-sensitive adhesive after leaving the extrusion equipment, more preferably at least 15K, especially at least 20K. But basically it seems that it is not only the temperature of the adhesive in the kneaded material that will affect the formation of the gradient according to the present invention on the volume ratio of the micro-balloons, but also the residence time of the adhesive in the kneaded material. As such, it has been found that in a mode of operation with a large kneaded diameter (which results in a longer residence time of the adhesive in the kneaded material), there has been a sufficiently low temperature difference to produce a pressure-sensitive adhesive according to the present invention. .

Therefore, it is particularly preferred that the temperature of the pressure-sensitive adhesive in the kneaded product is 1 to 5 cm, which is higher than the elongation of the kneaded product that is orthogonal to the plane extending from the mechanical direction and the calender nip. The temperature of the current pressure-sensitive adhesive after extrusion equipment is 10 to 20 K, and the elongation of the kneaded product is 5 to 10 cm orthogonal to the plane extending from the mechanical direction and the calender roll nip, which is higher than that when leaving The temperature of the current pressure-sensitive adhesive after extrusion equipment is 6 to 10K.

It has been found that the higher the difference between the temperature of the pressure-sensitive adhesive and the temperature of the kneaded product after leaving the extrusion equipment, the more pronounced the volume ratio gradient of the micro-balloon, and thus the possibility of controlling the gradient. As another control variable, the diameter of the kneaded product can be used as described above, because as the diameter increases, the residence time of the adhesive in the kneaded product increases.

Of course, the method according to the present invention is preferably performed in a manner that does not allow the expanded microballoons to shrink or even destroy. Each micro-balloon type can specify a maximum temperature T _max that a micro-balloon can heat without shrinking or even destroying it. In this view, the temperature of the current pressure-sensitive adhesive after leaving the extrusion equipment is preferably at least 10% lower than the _{Tmax of the} relevant microballoon type, more preferably at least 15%, and especially at least 20%.

Another application of the present invention is the use of a tape-shaped pressure-sensitive adhesive foamed with micro-balloons according to the present invention, or the use of a tape-shaped pressure-sensitive adhesive foamed with micro-balloons manufactured according to the method of the present invention, It is a component for bonding electronic devices (especially displays), or a component in or on a car, especially for bonding electronic components in a car, and for bonding a trim or a badge to a car varnish. Especially when high-priced components of electronic devices (such as displays) are glued, it is particularly advantageous to be able to reposition the components already mentioned. Adhesion using the pressure-sensitive adhesive according to the present invention can be performed manually and automatically.

    [Example]         Test Methods    

Test 1: Adhesion to steel

Adhesion is measured in a test environment at a temperature of 23 ° C +/- 1 ° C and a relative humidity of 50% +/- 5%. The specimen was cut to a width of 20 mm and adhered to a steel plate (SUS). The steel plate was cleaned and conditioned before testing. For this reason, the board is first washed with a solvent and then allowed to stand in the air for 5 minutes, whereby the solvent can be evaporated. The side of the tape facing away from the test substrate was then covered with a 75 μm thick etched PET film, thereby preventing the specimen from stretching during the test. The test specimen is then rolled onto the substrate. To this end, a 4 kg roller was rolled back and forth across the tape five times at a roll speed of 10 m / min. After 1 minute or 14 days of rolling, the board is advanced into a special support, which allows the sample to be pulled out at a specific angle (listed in the test results). Adhesion measurement was performed using a Zwick tensile tester. The measurement results are in N / cm, and five separate measurements are averaged.

    Preparation of polyacrylate base polymer:    

A conventional reactor for radical polymerization was charged with 72.0 kg of 2-ethylhexyl acrylate, 20.0 kg of methyl acrylate, 8.0 kg of acrylic acid, and 66.6 kg of acetone / isopropanol (94: 6). After stirring nitrogen for 45 minutes, the reactor was heated to 58 ° C, and 50 g of AIBN dissolved in 500 g of acetone was added. Next, the external heating bath was heated to 75 ° C, and the reaction was continued at this external temperature. After 1 hour, 50 g of AIBN dissolved in 500 g of acetone was added again, and after 4 hours, it was diluted with 10 kg of an acetone / isopropanol mixture (94: 6).

After 5 hours and 7 hours, starting again with 150 g of bis (4-tert-butylcyclohexyl) peroxydicarbonate dissolved in 500 g of acetone. The reaction was stopped after a reaction time of 22 hours and cooled to room temperature. The product had a solids content of 55.8% and was dried. The K value of the resulting polyacrylate was 58.9, the average molecular weight Mw = 748.000 g / mol, the polydispersity D (Mw / Mn) = 8.9, and the static glass transition temperature Tg = -35.2 ° C.

    Example 1:    

Synthetic rubber Kraton D1118 and Expancel 920DU40 micro balloons were added to the planetary screw extruder through a solid feeder. In addition, the anti-aging agent Irganox 1726 in a molten state and the solid-state anti-aging agent Irganox 1076 were added to a planetary screw extruder. After the synthetic rubber is melted, the terpene phenolic resin Dertophene T105 and the polyacrylate base polymer are added, which are respectively pre-melted in a single screw extruder. After the ingredients are thoroughly mixed, the cross-linking agent UVACure 1500 is added to the final roller of the planetary screw extruder. The melt is then transferred to a twin-screw extruder, which is degassed by applying negative pressure and conveyed to a twin-screw calender through a wide slot nozzle. The structure is formed into a flat tape between two siliconized PET films. The process parameters for the jacket temperature and the number of revolutions in the twin-screw extruder were selected so that the temperature of the melt at the nozzle outlet (measured by Fluke's IR thermometer Ti20 type) was 149 ° C. Coating was performed by a twin-screw calender at a screw temperature of 110 ° C., wherein the feed of the calender was performed in such a manner that a kneaded material having a diameter of 2 cm was formed before the calender roll. The surface temperature of the kneaded material measured by an IR thermometer (Fluke, Ti20 type) reached 155 ° C. The coated product has a layer thickness of 325 μm and an average density of 830 kg / m ³ , where the porosity at a depth of 20 μm measured by μCT is on the covering side (the side of the tape, and the unwinded backing paper is on it) is 24%, and 28% on the open side.

The composition of the pressure-sensitive adhesive is 58.7% polyacrylate, 25.4% Kraton D1118, 14.2% Dertophene T105, 1.1% Expancel 920DU40, 0.3% Irganox 1726, 0.2% Irganox 1076, and 0.1% UVACure1500 (data in% by weight).

    Example 2:    

The process and formulation are as in Example 1. However, the parameters of the jacket screw temperature and the number of revolutions of the twin-screw extruder were selected so that the temperature of the melt at the nozzle outlet was 139 ° C. The coating was performed by a twin-screw calender at a screw temperature of 110 ° C., and the feed of the calender was performed in such a manner that a kneaded material having a diameter of 5 cm was formed before the calender roll. The surface temperature of the kneaded product reached 152 ° C. The coated product had a layer thickness of 280 μm and an average density of 878 kg / m ³ , wherein the porosity at a depth of 20 μm measured by μCT was 18% on the covered side and 30% on the open side.

The composition of the pressure-sensitive adhesive is 58.8% polyacrylate, 25.4% Kraton D1118, 14.2% Dertophene T105, 1.0% Expancel 920DU40, 0.3% Irganox 1726, 0.2% Irganox 1076, and 0.1% UVACure1500 (data in% by weight).

    Example 3:    

The process and formulation are as in Example 1. However, the parameters of the jacket screw temperature and the number of revolutions of the twin-screw extruder were selected so that the temperature of the melt at the nozzle outlet was 134 ° C. The coating was performed by a twin-screw calender at a screw temperature of 110 ° C., and the feed of the calender was performed in such a manner that a kneaded material having a diameter of 8 cm was formed before the calender roll. The surface temperature of the kneaded product reached 153 ° C. The coated product had a layer thickness of 280 μm and an average density of 908 kg / m ³ , wherein the porosity at a depth of 20 μm measured by μCT was 12% on the covered side and 30% on the open side.

The composition of the pressure-sensitive adhesive is 58.8% polyacrylate, 25.4% Kraton D1118, 14.2% Dertophene T105, 1.0% Expancel 920DU40, 0.3% Irganox 1726, 0.2% Irganox 1076, and 0.1% UVACure1500 (data in% by weight).

    Example 4:    

The process and formulation are as in Example 1. However, the parameters of the jacket screw temperature and the number of revolutions of the twin-screw extruder were selected so that the temperature of the melt at the nozzle outlet was 131 ° C. The coating was performed by a twin-screw calender at a screw temperature of 110 ° C., and the feed of the calender was performed in such a manner that a kneaded material having a diameter of 8 cm was formed before the calender roll. The surface temperature of the kneaded product reached 151 ° C. The coated product had a layer thickness of 280 μm and an average density of 922 kg / m ³ , wherein the porosity at a depth of 20 μm measured by μCT was 7% on the covered side and 30% on the open side.

The composition of the pressure-sensitive adhesive is 58.8% polyacrylate, 25.4% Kraton D1118, 14.2% Dertophene T105, 1.0% Expancel 920DU40, 0.3% Irganox 1726, 0.2% Irganox 1076, and 0.1% UVACure1500 (data in% by weight).

    Example 5:    

The process and formulation are as in Example 1. However, the parameters of the jacket screw temperature and the number of revolutions of the twin screw extruder were selected so that the temperature of the melt at the nozzle outlet was 127 ° C. The coating was performed by a twin-screw calender at a screw temperature of 110 ° C., and the feed of the calender was performed in such a manner that a kneaded material having a diameter of 8 cm was formed before the calender roll. The surface temperature of the kneaded product reached 153 ° C. The coated product had a layer thickness of 305 μm and an average density of 947 kg / m ³ , wherein the porosity at a depth of 20 μm measured by μCT was 4% on the covered side and 32% on the open side.

The composition of the pressure-sensitive adhesive is 58.8% polyacrylate, 25.4% Kraton D1118, 14.2% Dertophene T105, 1.0% Expancel 920DU40, 0.3% Irganox 1726, 0.2% Irganox 1076, and 0.1% UVACure1500 (data in% by weight).

    Example 6:    

The process and formulation are as in Example 1. However, the parameters of the jacket screw temperature and the number of revolutions of the twin-screw extruder were selected so that the temperature of the melt at the nozzle outlet was 131 ° C. The coating was performed by a twin-screw calender at a screw temperature of 110 ° C., and the feed of the calender was performed in such a manner that a kneaded material having a diameter of 8 cm was formed before the calender roll. The surface temperature of the kneaded product reached 157 ° C. The coated product had a layer thickness of 450 μm and an average density of 910 kg / m ³ , wherein the porosity at a depth of 20 μm measured by μCT was 7% on the covered side and 32% on the open side.

The composition of the pressure-sensitive adhesive is 58.8% polyacrylate, 25.4% Kraton D1118, 14.2% Dertophene T105, 1.0% Expancel 920DU40, 0.3% Irganox 1726, 0.2% Irganox 1076, and 0.1% UVACure1500 (data in% by weight).

    Example 7:    

The process and formulation are as in Example 1. However, the parameters of the jacket screw temperature and the number of revolutions of the twin-screw extruder were selected so that the temperature of the melt at the nozzle outlet was 147 ° C. The coating was performed by a twin-screw calender at a screw temperature of 100 ° C, and the feed of the calender was performed in such a manner that a kneaded product having a diameter of 6 cm was formed before the calender roll. The surface temperature of the kneaded product reached 161 ° C. The coated product had a layer thickness of 1150 μm and an average density of 793 kg / m ³ , wherein the porosity at a depth of 20 μm measured by μCT was 21% on the covered side and 36% on the open side.

The components of the pressure-sensitive adhesive are 58.6% polyacrylate, 25.4% Kraton D1118, 14.2% Dertophene T105, 1.2% Expancel 920DU40, 0.3% Irganox 1726, 0.2% Irganox 1076, and 0.1% UVACure1500 (data in% by weight).

    Comparative Example 1:    

Synthetic rubber Kraton D1118 and Expancel 920DU40 micro balloons were added to the planetary screw extruder through a solid feeder. In addition, the anti-aging agent Irganox 1726 in a molten state and the solid-state anti-aging agent Irganox 1076 were added to a planetary screw extruder. After the synthetic rubber is melted, the terpene phenolic resin Dertophene T105 and the polyacrylate base polymer are added, which are respectively pre-melted in a single screw extruder. After the ingredients are thoroughly mixed, the cross-linking agent UVACure 1500 is added to the final roller of the planetary screw extruder. The melt is then transferred to a twin-screw extruder, which is degassed by applying negative pressure and conveyed to a twin-screw calender through a wide slot nozzle. The structure is formed into a flat tape between two siliconized PET films. The process parameters for the jacket temperature and the number of revolutions in the twin-screw extruder were selected so that the temperature of the melt at the nozzle outlet (measured by Fluke's IR thermometer Ti20 type) was 158 ° C. The coating was carried out by a twin-screw calender at a screw temperature of 100 ° C., wherein the feed of the calender was performed in such a manner that a kneaded material having a diameter of 1 cm was formed before the calender roll. The surface temperature of the kneaded material measured by an IR thermometer (Fluke, Ti20 type) reached 162 ° C. The coated product had a layer thickness of 420 μm and an average density of 780 kg / m ³ , wherein the porosity at a depth of 20 μm measured by μCT was 29% on the covered side and 30% on the open side.

The composition of the pressure-sensitive adhesive is 58.7% polyacrylate, 25.4% Kraton D1118, 14.2% Dertophene T105, 1.1% Expancel 920DU40, 0.3% Irganox 1726, 0.2% Irganox 1076, and 0.1% UVACure1500 (data in% by weight).

    Comparative Example 2:    

The process and formulation are as in Comparative Example 1. However, the parameters of the jacket screw temperature and the number of revolutions of the twin-screw extruder were selected so that the temperature of the melt at the nozzle outlet was 164 ° C. The coating was performed by a twin-screw calender at a screw temperature of 100 ° C, and the feed of the calender was performed in such a manner that a kneaded product was not formed. The coated product had a layer thickness of 330 μm and an average density of 770 kg / m ³ , wherein the porosity at a depth of 20 μm measured by μCT was 31% on the covered side and 32% on the open side.

The components of the pressure-sensitive adhesive are 58.6% polyacrylate, 25.4% Kraton D1118, 14.2% Dertophene T105, 1.2% Expancel 920DU40, 0.3% Irganox 1726, 0.2% Irganox 1076, and 0.1% UVACure1500 (data in% by weight).

    The result    

aS = cover side

oS = open side

Claims (9)

    A tape-shaped pressure-sensitive adhesive foamed with micro-balloons, comprising-a blend of at least one poly (meth) acrylate and at least one synthetic rubber, and-a large number of inflatable micro-balloons, characterized in that : The proportion of micro-balloons in a volume formed by a part of an arbitrary tape surface on the upper side of the tape-shaped pressure-sensitive adhesive and a depth of 20 μm is a volume formed by a part of an arbitrary tape surface on the lower side and a depth of 20 μm. The proportion of medium and small balloons differs by at least 12%.         For example, the tape-shaped pressure-sensitive adhesive of claim 1, wherein the thickness of the tape-shaped pressure-sensitive adhesive is 50 to 1500 μm.         The tape-shaped pressure-sensitive adhesive according to any one of the above claims, wherein the pressure-sensitive adhesive comprises 40 to 70% by weight of at least one poly (meth) acrylate based on the total weight of the pressure-sensitive adhesive, and 15 ~ 50% by weight of at least one synthetic rubber.         The tape-shaped pressure-sensitive adhesive according to any one of the above claims, wherein the pressure-sensitive adhesive comprises at least one tackifier compatible with poly (meth) acrylate.     The tape-shaped pressure-sensitive adhesive according to any one of the above claims, wherein the synthetic rubber is a block copolymer having an AB, ABA, (AB) _n , (AB) _n X, or (ABA) _n X structure, where- Block A each independently represents a polymer formed by polymerizing at least one vinyl aromatic hydrocarbon;-Block B each independently represents a polymer formed by polymerizing a conjugated diene and / or isobutylene having 4 to 18 carbon atoms Polymer, or a partially or fully hydrogenated derivative of such a polymer;-X represents the residue of a coupling agent or initiator, and-n represents An integer of two.     A method for manufacturing a tape-shaped pressure-sensitive adhesive foamed with micro-balloons, comprising: a) preparing a pressure-sensitive adhesive, the pressure-sensitive adhesive comprising:-synthesized from at least one poly (meth) acrylate and at least one A blend of rubber, and-a large number of expandable micro-balloons; b) forming the pressure-sensitive adhesive into a belt shape in a calender nip, wherein the pressure-sensitive adhesive is placed before the calender nip The way of forming a kneaded product passes through the calender nip, and-the temperature of the pressure-sensitive adhesive in the kneaded material exceeds the expansion temperature of the microballoon, and-the temperature of the pressure-sensitive adhesive in the kneaded material is higher than that of the manufacturing The temperature of the current pressure-sensitive adhesive is at least 5K.         The manufacturing method of claim 6, wherein the manufacturing method is a continuous method.         The manufacturing method of claim 6 or 7, wherein the preparation of the pressure-sensitive adhesive includes passing through a kneading equipment and an extrusion equipment; the temperature of the current pressure-sensitive adhesive after leaving the extrusion equipment exceeds the expansion temperature of the micro-balloons The temperature of the pressure-sensitive adhesive in the kneaded product is at least 5K higher than the temperature of the pressure-sensitive adhesive at the moment after leaving the extrusion equipment.         A tape-shaped pressure-sensitive adhesive foamed with microballoons according to any one of claims 1 to 5 or foamed with microballoons manufactured by a method according to any one of claims 6 to 8 The use of a tape-shaped pressure-sensitive adhesive is used for bonding components of electronic devices or components in automobiles.