A high-residue, low-climbing photocurable silicone release agent composition, its preparation method, and its application.

Abstract

This invention relates to a high-residue, low-climbing photocurable silicone release agent composition, its preparation method, and its application, comprising the following components: Component A: a linear polydimethylsiloxane containing one or two (meth)acryloyloxy groups at each end of the molecular chain; Component B: a polydimethylsiloxane with trimethylsilyl end groups and 3-5 (meth)acryloyloxy side groups on the molecular chain; Component C: a polydimethylsiloxane with trimethylsilyl end groups, and a molecular structure containing at least one T or Q structure and 3-5 (meth)acryloyloxy groups; Component D: a carboxylic acid containing photocurable unsaturated double bonds or a phosphate ester tackifying monomer containing photocurable unsaturated double bonds; Component E: a photoinitiator. The high-residue, low-climbing photocurable silicone release agent composition of this invention has all components participating in the photocuring reaction, reducing inert components, effectively improving release force climb, and significantly increasing the residue of the pressure-sensitive adhesive.

Description

Technical Field

[0001] This invention relates to the field of silicone release agents, specifically to a high-residue, low-climbing photocurable silicone release agent composition, its preparation method, and its application. Background Technology

[0002] Release agents are mainly divided into two categories: silicone release agents and non-silicone release agents. Silicone release agents are widely used in release coatings, such as pressure-sensitive adhesive protective films and labels, due to their low surface energy, excellent high and low temperature resistance, long-term weather resistance, and good flowability. Common silicone release agents are mainly based on hydrosilylation curing systems and can be divided into three types: solvent-based, solvent-free, and emulsion-based.

[0003] Solvent-based release agents use volatile solvents such as toluene and xylene, which are restricted due to health and environmental concerns. Emulsion-based release agents, while solvent-free, use water as a medium, resulting in poor coating uniformity and slow evaporation. Solvent-free release agents are more environmentally friendly, but like other systems, their curing requires heating, typically above 100°C. This is unsuitable for heat-sensitive substrates, easily leading to problems such as curling and embrittlement. Furthermore, addition-type silicone release agents also face the problem of platinum catalyst poisoning, causing curing failure or incomplete curing.

[0004] Therefore, photocurable silicone release agents have received increasing attention and favor in recent years due to their advantages of curing without heating and being environmentally friendly and efficient.

[0005] Photocurable silicone release agents can be classified into free radical curing systems and cationic curing systems based on their curing principles. Among these, free radical curing systems are the most widely used photocurable release agents due to their wide range of adjustable release forces and lack of post-curing issues. Most commonly used release agent resins on the market have a linear structure, such as Evonik's... RC 902 is the main component, combined with resins containing hydroxyl and acryloyl groups (such as... RC 711 is used as an anchoring agent. After adding an initiator, it forms a release coating under light.

[0006] According to the MSDS (Material Safety Data Sheet) of the aforementioned products, the main chain of these resins is dimethylsiloxane, which has low surface energy and low polarity, resulting in weak adhesion to the substrate. During storage or after high-temperature aging, silicon migration is prone to occur, leading to a low residual release force value of the pressure-sensitive adhesive. Furthermore, due to the introduction of a large amount of hydroxyl-containing photocurable resin as an anchoring agent, the residual hydroxyl groups may slowly react with or enhance the interaction with the polar functional groups in the pressure-sensitive adhesive, causing a gradual increase in release force and a significant release force creep problem. Summary of the Invention

[0007] The technical problem solved by the present invention is to provide a photocurable silicone release agent composition with high residual and low creep.

[0008] The technical solution adopted by this invention to solve its technical problem is:

[0009] A high-residue, low-climbing photocurable silicone release agent composition comprising the following components:

[0010] Component A: A linear polydimethylsiloxane containing one or two (meth)acryloyloxy groups at each end of its molecular chain;

[0011] Component B: Polydimethylsiloxane with trimethylsilyl end groups and 3-5 (meth)acryloyloxy groups on the side groups of the molecular chain;

[0012] Component C: Polydimethylsiloxane with trimethylsilyl end groups on the molecular chain and containing at least one T or Q structure and 3-5 (meth)acryloyloxy groups;

[0013] Component D: Carboxylic acid containing photocurable unsaturated double bonds or phosphate ester thickening monomer containing photocurable unsaturated double bonds;

[0014] Component E: Photoinitiator.

[0015] Furthermore, the molecular chain of component A has a linear structure, and each of the two molecular chains contains one or two (meth)acryloyloxy groups at its ends. Component A has the molecular structural formula shown in Formula I:

[0016]

[0017] Wherein, Z is a divalent hydrocarbon group with 2-10 carbon atoms, including methylene, ethylene, and propylene; or a divalent hydrocarbon group containing at least one heteroatom of oxygen, nitrogen, or sulfur, such as a divalent functional group with the structural formula II; R1 is methyl or hydrogen; m is an integer of 1 or 2, and x is any value from 10 to 200, satisfying that the viscosity of component A at 25°C is 100 mPa·s to 2000 mPa·s;

[0018]

[0019] Furthermore, the terminal group of component B is a trimethylsilyl group, and the polydimethylsiloxane with 3-5 (meth)acryloyloxy groups on the side chain has a linear structure. Component B has the molecular structural formula shown in Formula III:

[0020]

[0021] Wherein, Z is a divalent hydrocarbon group with 2-10 carbon atoms, including methylene, ethylene, and propylene; or a divalent hydrocarbon group containing at least one heteroatom of oxygen, nitrogen, or sulfur, such as a divalent functional group with the structural formula II; R1 is methyl or hydrogen; any value of 3 ≤ n ≤ 5, and m is any value of 10 to 200, such that the structure of formula III contains 3 to 5 (meth)acryloyloxy groups, and m + n makes the viscosity of component B at 25°C be 100 mPa·s to 2000 mPa·s.

[0022]

[0023] Furthermore, the molecular chain end group of component C is trimethylsilyl, and the molecular structure contains at least one T or Q structure and contains 3-5 (meth)acryloyloxy groups of polydimethylsiloxane, and component C has the molecular structure shown in Formula IV.

[0024] (Me3SiO 0.5 ) r (MeR 2 SiO) s (R 3 SiO 1.5 ) t (SiO2) u Formula IV,

[0025] Among them, Me3SiO 0.5 Representing the M-structure, MeR 2 SiO represents the D structure, R 3 SiO 1.5 The T structure is represented by M, and the Q structure is represented by SiO2. The M structure refers to a structure with three hydrocarbon groups directly bonded to the Si atom, the D structure refers to a structure with two hydrocarbon groups directly bonded to the Si atom, the T structure refers to a structure with one hydrocarbon group directly bonded to the Si atom, and the Q structure refers to a structure with no hydrocarbon groups directly bonded to the Si atom.

[0026] Where Me is methyl, R 2 R 3 This indicates a methyl group or a functional group of formula V containing a photocurable (methacryloyloxy) group, and R 2 R 3 It contains at least 3 to 5 functional groups with the structure of formula V;

[0027] The M structure has a chain segment number r > 0; the D structure has a chain segment number s > 0; the T structure has a chain segment number t ≥ 0; the Q structure has a chain segment number u ≥ 0, and satisfies t + u ≥ 1, that is, there is at least one T or Q chain segment; the structure of formula IV needs to satisfy the ratio of the number of groups directly connected to silicon atoms to the number of groups of Si atoms, that is, R / Si satisfies 1.5 ≤ (3r + 2S + t) / (r + s + t + u) ≤ 2.0, and make (C) satisfy the viscosity of 100 mPa.s to 2000 mPa.s at 25°C, preferably 300 mPa.s to 800 mPa.s;

[0028]

[0029] Furthermore, the three resins, component A, component B, and component C, constitute the base polymer of the release agent composition. The content of component A is 30-70 parts, the content of component B is 10-50 parts, the content of component C is 5-30 parts, and the total amount of component A, component B, and component C is 100 parts.

[0030] Furthermore, the carboxylic acid monomer containing photocurable unsaturated double bonds in component D includes one or more of acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, and fumaric acid; the phosphate ester thickening monomer containing photocurable unsaturated double bonds in component D includes one or more of Sartoma SR9051, Changxing EM39, Kyoei P-1M or P-2M from Japan.

[0031] The component D includes one or more of carboxylic acids containing photocurable unsaturated double bonds or phosphate ester tackifying monomers containing photocurable unsaturated double bonds, and the content of the component D is 1 to 5 parts.

[0032] Furthermore, component E includes benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, hydroxydimethylacetophenone, dimethylaminoacetophenone, dimethoxy-2-phenylacetophenone, 3-methylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 4-chloroacetophenone, 4,4-dimethoxyacetophenone, 2-Hydroxy-2-methyl-1-phenylpropane-1-one, 4-hydroxycyclobenzophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4′-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2-methylanthraquinone, 2 2-Ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, β-chloroanthraquinone, 2-methylthioxanthraquinone, 2-ethylthioxanthraquinone, 2-chlorothioxanthraquinone, 2,4-dimethylthioxanthraquinone, 2,4-diethylthioxanthraquinone, phenyl dimethyl ketone, benzophenone benzyl dimethyl ketone, acetylphenyl dimethyl ketone, p-dimethylaminobenzoate, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, fluorene, triphenylamine, carbazole, benzyl diphenyl ether One or more of the following: phenyl sulfide, tetramethylthiourea monosulfide, ethyl(2,4,6-trimethylbenzoyl)phenylphosphonate, 1-hydroxycyclohexylphenyl ketone, 2-[2-oxo-2-phenylethoxy-ethoxy]-ethyl oxyphenylacetic acid, 2-[2-hydroxy-ethoxy]-ethyl oxyphenylacetic acid, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and phosphine bis(2,4,6-trimethylbenzoyl).

[0033] Furthermore, the composition also includes a modified photocurable polydimethylsiloxane containing hydroxyl and acrylic functional groups, a solvent, a leveling agent, a defoamer, a coupling agent, and a filler.

[0034] Preferably, the composition does not contain a solvent.

[0035] A method for preparing a release film, based on the above-mentioned high-residue, low-climbing photocurable silicone release agent composition, includes the following steps:

[0036] Step S1: Mix components A, B, C, D, and E thoroughly in a dark environment to form a mixture;

[0037] Step S2: Apply the mixture to the substrate surface using a slit, gravure, or roller coating method;

[0038] Step S3: After being exposed to UV light, it is cured into a release film.

[0039] The beneficial effects of this invention are:

[0040] To address the aforementioned problems, this invention employs a compound formulation of the following five components, successfully resolving the issues of high release force creep and low pressure-sensitive adhesive residue:

[0041] 1. (A) A linear polydimethylsiloxane with one or two (meth)acryloyloxy groups at both ends, the main chain being dimethylsiloxane segments, which endows the system with excellent release properties;

[0042] 2. (B) Polydimethylsiloxane with trimethylsilyl end group and 3-5 (meth)acryloyloxy groups on the side group. After curing, the end group migrates to the surface through molecular motion, thereby stabilizing the release force.

[0043] 3. (C) Polydimethylsiloxane with trimethylsilyl end group, containing T or Q structure in molecular structure and 3-5 (meth)acryloyloxy groups. The T or Q structure enhances the affinity with the substrate. When combined with a small amount of (D) tackifying monomer (such as carboxylic acid or phosphate ester containing photocurable unsaturated double bonds), it significantly improves adhesion and reduces the residue of polar functional groups, inhibiting release force climbing.

[0044] 4. Contains photocurable unsaturated double bonds as a tackifying monomer to improve the adhesion of the system;

[0045] 5. Photoinitiator, which promotes the efficient completion of the photocuring reaction.

[0046] All components participate in the photocuring reaction, reducing inert components, which not only effectively improves release force creep but also significantly reduces pressure-sensitive adhesive residue. Detailed Implementation

[0047] To make the above-mentioned contents, objectives, and beneficial effects of the present invention more apparent and understandable, the specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0048] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] This invention provides a high-residue, low-creep photocurable silicone release agent composition, comprising the following components:

[0050] Component A: A linear polydimethylsiloxane containing one or two (meth)acryloyloxy groups at each end of its molecular chain;

[0051] Component B: Polydimethylsiloxane with trimethylsilyl end groups and 3-5 (meth)acryloyloxy groups on the side groups of the molecular chain;

[0052] Component C: Polydimethylsiloxane with trimethylsilyl end groups on the molecular chain and containing at least one T or Q structure and 3-5 (meth)acryloyloxy groups;

[0053] Component D: Carboxylic acid containing photocurable unsaturated double bonds or phosphate ester thickening monomer containing photocurable unsaturated double bonds;

[0054] Component E: Photoinitiator.

[0055] Furthermore, the molecular chain of component A has a linear structure, and the ends of both molecular chains contain one or two (meth)acryloyloxy groups, which have the molecular structure shown in structure (I):

[0056]

[0057] Wherein, Z is a divalent hydrocarbon group with 2-10 carbon atoms, such as methylene, ethylene, propylene, etc.; or a divalent hydrocarbon group containing at least one heteroatom such as oxygen, nitrogen, or sulfur, such as the divalent functional group with structural formula (II). In structural formula (II), p and q are integers from 0 to 10, preferably propylene or the divalent functional group with structural formula (II).

[0058] Wherein, R1 is methyl or hydrogen, with hydrogen being preferred from the perspective of curing activity. m is an integer of 1 or 2. x is any value from 10 to 200, satisfying that the viscosity of component A at 25°C is 100 mPa·s to 2000 mPa·s, preferably 300 mPa·s to 800 mPa·s.

[0059]

[0060] Component A can be obtained through various methods such as hydrosilylation, urethane esterification, and esterification. For example, referring to the US patent for acrylic functional silicone resin composition (publication number: US4568566A), it is obtained by hydrosilylation reaction of polydimethylsiloxane with hydrogen-containing ends on both sides of the molecular chain with allyl acrylate and other substances.

[0061] Component A can also be obtained through commercial means, such as Evonik Chemicals. RC 902 RC922, Changxing Chemical's ETERAD 4605, and Mihama Co., Ltd.'s Silmer ACR Di-50, and Zhanxin's 350, etc.

[0062] Furthermore, the structural formula of component B is as described in (III). The end group of component B is trimethylsilyl, and the polydimethylsiloxane with 3-5 (meth)acryloyloxy groups on the side of the molecular chain has a linear structure.

[0063]

[0064] Wherein, Z and R1 are defined the same as in structure (I), preferably Z is propylene and R1 is hydrogen. Any value of 3 ≤ n ≤ 5, and any value of m from 10 to 200, such that the structure of (III) contains 3 to 5 (meth)acryloyloxy groups, and m + n ensures that component B has a viscosity of 100 mPa·s to 2000 mPa·s at 25°C, preferably 300 mPa·s to 800 mPa·s.

[0065] Component B can be obtained by acid-catalyzed equilibrium reaction of cyclic compounds containing (meth)acryloyloxy groups and dimethylsiloxane cyclic compounds with corresponding end-capping agents, or by hydrolysis-condensation reaction of corresponding alkoxysilanes.

[0066] Furthermore, component C has a trimethylsilyl end group and a molecular structure containing at least one T or Q structure and 3-5 (meth)acryloyloxy groups, forming a polydimethylsiloxane. Due to the introduction of a branched structure, it has a three-dimensional structure, as shown in formula (IV).

[0067] (Me3SiO 0.5 ) r (MeR 2 SiO) s (R 3 SiO 1.5 ) t (SiO2) u Formula (IV)

[0068] In the above structural formula, Me3SiO 0.5 Representing the M-structure, MeR 2 SiO represents the D structure, R 3 SiO 1.5 The T-structure is represented by M, and the Q-structure by SiO2. The naming conventions for M, D, T, and Q are industry-standard: M indicates three hydrocarbon groups directly bonded to the Si atom; D indicates two hydrocarbon groups directly bonded to the Si atom; T indicates one hydrocarbon group directly bonded to the Si atom; and Q indicates no hydrocarbon groups directly bonded to the Si atom.

[0069] In structural formula (IV), Me represents methyl, and R... 2 R 3This indicates a methyl group or a structure (V) containing a photocurable (methacryloyloxy) functional group, and R 2 R 3 The release agent composition contains at least 3 to 5 functional groups with the structure (V), where the structures of Z and R1 in formula V are the same as described above. The number of chain segments in M ​​is r > 0; the number of chain segments in D is s > 0; the number of chain segments in T is t ≥ 0; and the number of chain segments in Q is u ≥ 0, satisfying t + u ≥ 1, meaning there is at least one T or Q chain segment. To ensure the release agent composition has coatability, the structure (IV) must satisfy the ratio of the number of groups directly bonded to silicon atoms to the number of groups on Si atoms, i.e., R / Si must satisfy 1.5 ≤ (3r + 2S + t) / (r + s + t + u) ≤ 2.0, and (C) must satisfy a viscosity of 100 mPa·s to 2000 mPa·s, preferably 300 mPa·s to 800 mPa·s, at 25°C.

[0070]

[0071] The preparation method of component C can refer to that of component B, using the corresponding alkoxysilane, obtained by hydrolysis and condensation reaction under acidic conditions.

[0072] Furthermore, the present invention provides a high-residue, low-climbing photocurable silicone release agent composition, comprising three resins, component A, component B, and component C, which constitute the base polymer of the release agent composition. Component A is present in a content of 30-70 parts, component B in a content of 10-50 parts, and component C in a content of 5-30 parts, with the total amount of components A, B, and C being 100 parts.

[0073] Furthermore, component D is a carboxylic acid containing a photocurable unsaturated double bond or a phosphate ester tackifying monomer containing a photocurable unsaturated double bond. The carboxylic acid monomer containing a photocurable unsaturated double bond includes one or more of acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, and fumaric acid; the phosphate ester tackifying monomer containing a photocurable unsaturated double bond includes one or more of Sartoma SR9051, Changxing EM39, and Kyoei-sha PM-2.

[0074] The tackifying monomer D is one or more of the above-mentioned carboxylic acids containing photocurable unsaturated double bonds or phosphate ester tackifying monomers containing photocurable unsaturated double bonds. Compared with 100 parts of the base polymer composed of component A, component B and component C, the content of tackifying monomer D is 1 to 5 parts, preferably 2 to 3 parts.

[0075] Furthermore, component E is a photoinitiator, which serves to fully cure the release agent composition; its type or variety is not particularly limited. Common photoinitiators can be used in this invention, examples of which include, but are not limited to: benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, hydroxydimethylacetophenone, dimethylaminoacetophenone, dimethoxy-2-phenylacetophenone, 3-methylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 4-chloroacetophenone, 4,4- Dimethoxyacetylbenzene, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4-hydroxycyclobenzophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4′-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2-methylanthraquinone, 2- Ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, β-chloroanthraquinone, 2-methylthioxanthraquinone, 2-ethylthioxanthraquinone, 2-chlorothioxanthraquinone, 2,4-dimethylthioxanthraquinone, 2,4-diethylthioxanthraquinone, phenyl dimethyl ketone, benzophenone benzyl dimethyl ketone, acetylphenyl dimethyl ketone, p-dimethylaminobenzoate, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, fluorene, triphenylamine, carbazole, benzyl diphenyl sulfide, tetramethyl sulfide Urea monosulfide, ethyl (2,4,6-trimethylbenzoyl)phenylphosphonate, 1-hydroxycyclohexylphenyl ketone, 2-[2-oxo-2-phenylethoxy-ethoxy]-ethyl oxyphenylacetic acid, 2-[2-hydroxy-ethoxy]-ethyl oxyphenylacetic acid, 2-hydroxy-2-methyl-1-phenyl-1-propanone, phosphine bis(2,4,6-trimethylbenzoyl), etc., the above photoinitiators can be used alone or in combination.

[0076] To improve compatibility with organosilicon, it is generally necessary to introduce functional groups containing long carbon chains into the initiator. This can be prepared using the method described in the US patent (Publication No.: US-7250204-B2), or commercially available brands such as those from Evonik Chemical can be used. Photoinitiator A18.

[0077] Compared to 100 parts of a base polymer composed of components A, B and C, the initiator content is 0.5 to 5 parts, preferably 1 to 2 parts.

[0078] Furthermore, the high residual low creep photocurable silicone release agent composition of the present invention also contains other components, such as modified photocurable polydimethylsiloxane containing hydroxyl and acrylic functional groups, solvents, leveling agents, defoamers, coupling agents, fillers, and other components. The addition of other components does not affect the performance of the release agent, ensuring that the release agent composition exhibits good adhesion to chlorinated polypropylene (CPP), polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET) films after photocuring irradiation. After aging at 70°C for 24 hours or 25°C for 7 days, it also exhibits good adhesion to... The release force creep of 7475 tape is less than 30%, and the adhesive residue of Nitto 31B tape is greater than 85%. From an environmental and occupational health perspective, the above release agent composition preferably does not contain solvents.

[0079] Furthermore, the high-residue, low-climbing photocurable silicone release agent composition of the present invention is prepared by uniformly mixing the above-mentioned components A, B, C, D, and E in a light-protected environment. The mixing equipment can be a planetary mixer, a high-speed mixer, etc., and there are no special restrictions on the order of adding components A, B, C, D, and E. After the above composition is uniformly mixed, it can be coated on the surface of the substrate by slit coating, gravure coating, roller coating, etc., and cured into the desired release film after UV irradiation.

[0080] Synthetic Example 1: (Linear polydimethylsiloxane with a trimethylsilyl end group and four methacryloyloxy groups on the side groups, B1)

[0081] In a 5L four-necked flask equipped with a stirrer, condenser, and temperature display, 68.9g (0.1mol) of 1,3,5,7-tetramethyl-1,3,5,7-tetraacryloyloxypropylcyclotetrasiloxane (CAS: 71550-64-6), 16.2g of hexamethyldisiloxane (MM, 0.1mol, CAS: 107-46-0), and 592g of octamethylcyclotetrasiloxane (D4, 2mol, CAS: 556-67-2) were added. 0.68g of hydroquinone was added as a polymerization inhibitor, and 1.5g of methanesulfonic acid was added as a catalyst. The reaction was carried out at 90-100℃ for 5h.

[0082] Then, after cooling to 50℃, 15g of sodium bicarbonate was added for neutralization and filtration. Following vacuum distillation at 120℃, an acryloyloxy-modified polydimethylsiloxane with a room temperature viscosity of 386 mPa·s and a refractive index of 1.4173 was obtained, with the following structure:

[0083]

[0084] Synthesis Example 2: (A polysiloxane resin with a trimethylsilyl end group of the molecular chain and containing at least one T or Q structure and 5 acryloyloxy groups, C1)

[0085] In a 5L four-necked flask equipped with a condenser, stirrer, temperature control device, and constant-pressure dropping funnel, 100g of 36.5% concentrated hydrochloric acid, 400g of distilled water, and 23.4g of hexamethyldisiloxane (MM, 0.15mol, CAS: 107-46-0) were added sequentially. After the material temperature was raised to 70℃, 23.4g of acryloyloxypropyltrimethoxysilane (0.1mol, CAS: 4369-14-6) and 87.2g of acryloyloxypropylmethyldimethoxysilane (0.1mol, CAS: 4369-14-6) were added dropwise through the constant-pressure dropping funnel. A mixture of 0.4 mol (CAS: 13732-00-8) and 960 g of dimethyldimethoxysilane (CAS: 1112-39-6) was added dropwise over 45 min. The mixture was then subjected to hydrolysis and condensation reaction at 70-80 °C for 4 h. 2000 g of toluene was added for extraction. The acidic aqueous layer was removed using a separatory funnel. The organic layer was repeatedly washed with water three times until neutral. The product was then pressure distilled at 120 °C to obtain an acryloxy-modified polysiloxane resin with a viscosity of 560 mPa·s and a refractive index of 1.4210. Its structure is as follows:

[0086] (Me3SiO 0.5 )3(Me2SiO) 80 (MeR A SiO)4(R A SiO 1.5 )1,

[0087] Among them, R A It is acryloyloxypropyl.

[0088] The raw materials used in the embodiments and comparative examples of this invention are as follows:

[0089] Component A1: Polydimethylsiloxane with acryloyloxy groups at the ends, Evonik RC 902 has a viscosity of 420 mPa·s and contains two acryloyloxy groups at each end.

[0090] Component A2: Polydimethylsiloxane with acryloyloxy groups at the ends, Silmer ACRDi-50 from Mihama Co., Ltd., with a viscosity of 120 mPa·s, containing one acryloyloxy group at each end.

[0091] Component B1: Acryloyloxy-modified polydimethylsiloxane obtained in Synthesis Example 1.

[0092] Component B2 (not of this invention): Modified polydimethylsiloxane with acryloyloxy and hydroxyl groups on the side groups, Evonik. RC 711 has a viscosity of 690 mPa·s.

[0093] Component C1: Acryloyloxy-modified polysiloxane resin obtained in Synthesis Example 2.

[0094] Component D1: Acrylic acid.

[0095] Component D2: 2-Methacryloxyethyl phosphate, P-1M, Kyoei Co., Ltd., Japan.

[0096] Component E1: Photoinitiator, TR-1173, Changzhou Qiangli New Materials.

[0097] Performance testing

[0098] To test the performance of the release agent composition of the present invention, example samples conforming to the present invention and comparative example samples not conforming to the present invention were applied to a sheet substrate (polyethylene terephthalate, PET film) by roll coating. The mixture was then subjected to a nitrogen atmosphere at 120 W / cm². 2 UV exposure intensity curing, conveyor belt speed 20m / min, coating amount approximately 1g / m 2 .

[0099] Release force test

[0100] Release force was measured using two types of 25mm wide adhesive tapes: specifically, an acrylic adhesive-coated tape (trade name: 7475) and tape coated with polyester adhesive (trade name Nitto Denko Nitto31B).

[0101] To measure release force (anti-sticking strength), these tapes were rolled onto the substrate and then tested at 70 g / cm². 2 The tapes were stored at 25°C under their own weight. After 24 hours, the force required to peel each tape from the substrate at a peel speed of 300 mm / min and a peel angle of 180° was measured and defined as the initial release force. This test procedure is substantially in accordance with FINAT Test Method No. 10.

[0102] To test aging performance, the storage time at 25°C was extended to 7 days or stored at 70°C for 24 hours, and the test was conducted under the same conditions. The measured release force is the aging release force.

[0103] Adhesive residue

[0104] The testing for adhesive residue was primarily conducted according to FINAT Test Method No. 11. For this purpose, Nitto 31B tape was rolled onto the release substrate and tested at 70 g / cm². 2Store at 25°C under its own weight. After 24 hours, detach the tape from the release substrate and roll it onto the designated substrate (steel plate, glass plate, and film).

[0105] After 1 minute, the force required to peel the tape from the substrate at a peel speed of 300 mm / min and a peel angle of 180° was measured. The measured value was compared with the measured value of untreated tape under the same test conditions, and the ratio was expressed as a percentage, which is the initial adhesive residue.

[0106] To test aging performance, the storage time at 25°C was extended to 7 days or stored at 70°C for 24 hours, and the test was conducted under the same conditions. The measured residue is the aging residue.

[0107] Adhesion test

[0108] The adhesion of the cured coating composition to the substrate is assessed by rubbing it firmly with the thumb. If the adhesion is insufficient, rubber-like debris will form.

[0109] In each embodiment and comparative embodiment, different components A, B, and C resins were combined to form a 100 base polymer, with a certain amount of tackifier and photoinitiator added. The formulations are shown in Table 1.

[0110] Table 1. Composition ratios of each embodiment and comparative embodiment

[0111]

[0112] The adhesion and initial release force properties of each embodiment are shown in Table 2:

[0113] Table 2 Adhesion and initial release performance of each embodiment

[0114]

[0115] Note: *OK indicates that the adhesion meets the requirements, meaning no rubber-like debris is produced; NG indicates that the adhesion does not meet the requirements, meaning rubber-like debris is produced.

[0116] As can be seen from Examples 1 and 2, using the three resins A1, B1, and C1 according to the present invention, regardless of whether a carboxylic acid containing a photocurable unsaturated double bond or a phosphate ester tackifying monomer containing a photocurable unsaturated double bond is used, the cured release agent can exhibit excellent adhesion. After aging at 70°C for 24 hours or 25°C for 7 days, the adhesion of the release agent to the mold is significantly improved. The release force creep of 7475 tape is less than 30%, while the adhesive residue of Nitto Denko 31B tape is greater than 90%.

[0117] As shown in Examples 2 and 3, using A1 with two acryloyloxy groups at the end groups or using A2 with one acryloyloxy group at each end group can result in excellent adhesion of the cured release agent. After aging at 70°C for 24 hours or 25°C for 7 days, the adhesion of the release agent to the end groups is significantly improved. The release force creep of 7475 tape is less than 30%, while the adhesive residue of Nitto Denko 31B tape is greater than 90%.

[0118] As can be seen from Comparative Example 1, when B2 containing acryloyloxy groups and hydroxyl groups is used, although the hydroxyl groups form good adhesion, a large amount of B2 results in more residual polar groups in the cured release agent, causing adhesion problems. The release force of 7475 tape increases by more than 30%.

[0119] According to Comparative Example 2, when no tackifying monomer is used, the adhesion of the cured release agent does not meet the requirements, and it also results in less than 90% adhesion residue on Nitto Denko 31B tape. This may be due to severe silicone migration caused by poor adhesion, which in turn leads to low residue.

[0120] According to Comparative Example 3, when C1 containing T or Q structure is not used, the adhesion of the cured release agent does not meet the requirements, and it also causes the adhesion residue of Nitto Denko 31B tape to be less than 90%. This may be due to the fact that the T or Q structure causes insufficient affinity of the release agent to the substrate, which in turn affects the adhesion and silicon migration.

[0121] According to Comparative Example 4, when A and C are used together, and B2 (not of this invention) is used to replace B1 of this invention, as well as the role of tackifier D, the adhesion meets the requirements, but the release force increases significantly by more than 30%.

[0122] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A photocurable silicone release agent composition with high residual and low creepage, characterized in that: Includes the following components: Component A: A linear polydimethylsiloxane containing one or two (meth)acryloyloxy groups at each end of its molecular chain; Component B: Polydimethylsiloxane with trimethylsilyl end groups and 3-5 (meth)acryloyloxy groups on the side groups of the molecular chain; Component C: Polydimethylsiloxane with trimethylsilyl end groups on the molecular chain and containing at least one T or Q structure and 3-5 (meth)acryloyloxy groups; Component D: Carboxylic acid containing photocurable unsaturated double bonds or phosphate ester thickening monomer containing photocurable unsaturated double bonds; Component E: Photoinitiator.

2. The high residual low creep photocurable silicone release agent composition according to claim 1, characterized in that: The molecular chain of component A has a linear structure, and each of the two molecular chains contains one or two (meth)acryloyloxy groups at its ends. Component A has the molecular structural formula shown in Formula I: Wherein, Z is a divalent hydrocarbon group with 2-10 carbon atoms, including methylene, ethylene, and propylene; or a divalent hydrocarbon group containing at least one heteroatom of oxygen, nitrogen, or sulfur, such as a divalent functional group with the structural formula II; R1 is methyl or hydrogen; m is an integer of 1 or 2, and x is any value from 10 to 200, satisfying that the viscosity of component A at 25°C is 100 mPa·s to 2000 mPa·s; 3. The high residual low creep photocurable silicone release agent composition according to claim 1, characterized in that: The polydimethylsiloxane with a trimethylsilyl end group of component B and 3-5 (meth)acryloyloxy groups on the side chain has a linear structure, and component B has the molecular structure shown in Formula III: Wherein, Z is a divalent hydrocarbon group with 2-10 carbon atoms, including methylene, ethylene, and propylene; or a divalent hydrocarbon group containing at least one heteroatom of oxygen, nitrogen, or sulfur, such as a divalent functional group with the structural formula II; R1 is methyl or hydrogen; any value of 3 ≤ n ≤ 5, and m is any value of 10 to 200, such that the structure of formula III contains 3 to 5 (meth)acryloyloxy groups, and m + n makes the viscosity of component B at 25°C be 100 mPa·s to 2000 mPa·s.

4. The high residual low creep photocurable silicone release agent composition according to claim 1, characterized in that: The molecular chain end group of component C is trimethylsilyl, and the molecular structure contains at least one T or Q structure and contains 3-5 (meth)acryloyloxy groups of polydimethylsiloxane. Component C has the molecular structure shown in Formula IV. (Me3SiO 0.5 ) r (MeR 2 (SiO) s (R 3 SiO 1.5 ) t (SiO2) u type IV, Among them, Me3SiO 0.5 Representing the M-structure, MeR 2 SiO represents the D structure, R 3 SiO 1.5 The T structure is represented by M, and the Q structure is represented by SiO2. The M structure refers to a structure with three hydrocarbon groups directly bonded to the Si atom, the D structure refers to a structure with two hydrocarbon groups directly bonded to the Si atom, the T structure refers to a structure with one hydrocarbon group directly bonded to the Si atom, and the Q structure refers to a structure with no hydrocarbon groups directly bonded to the Si atom. Where Me is methyl, R 2 R 3 This indicates a methyl group or a functional group of formula V containing a photocurable (methacryloyloxy) group, and R 2 R 3 It contains at least 3 to 5 functional groups with the structure of formula V; The M structure has a chain segment number r > 0; the D structure has a chain segment number s > 0; the T structure has a chain segment number t ≥ 0; the Q structure has a chain segment number u ≥ 0, and satisfies t + u ≥ 1, that is, there is at least one T or Q chain segment; the structure of formula IV needs to satisfy the ratio of the number of groups directly connected to silicon atoms to the number of groups of Si atoms, that is, R / Si satisfies 1.5 ≤ (3r + 2S + t) / (r + s + t + u) ≤ 2.0, and make (C) satisfy the viscosity of 100 mPa.s to 2000 mPa.s at 25°C, preferably 300 mPa.s to 800 mPa.s; 5. A high-residue, low-creep photocurable silicone release agent composition according to any one of claims 1-4, characterized in that: The three resins, A, B, and C, constitute the base polymer of the release agent composition. The content of component A is 30-70 parts, the content of component B is 10-50 parts, and the content of component C is 5-30 parts. The total amount of components A, B, and C is 100 parts.

6. The high residual low creep photocurable silicone release agent composition according to claim 5, characterized in that: The carboxylic acid monomers containing photocurable unsaturated double bonds in component D include one or more of acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, and fumaric acid; the phosphate ester thickening monomers containing photocurable unsaturated double bonds in component D include one or more of Sartoma SR9051, Changxing EM39, Kyoei P-1M or P-2M from Japan. The component D includes one or more of carboxylic acids containing photocurable unsaturated double bonds or phosphate ester tackifying monomers containing photocurable unsaturated double bonds, and the content of the component D is 1 to 5 parts.

7. The high residual low creep photocurable silicone release agent composition according to claim 5, characterized in that: Component E includes benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, hydroxydimethylacetophenone, dimethylaminoacetophenone, dimethoxy-2-phenylacetophenone, 3-methylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 4-chloroacetophenone, 4,4-dimethoxyacetophenone, 2-hydroxy 2-Methyl-1-phenylpropane-1-one, 4-hydroxycyclobenzone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4′-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2-methylanthraquinone, 2-ethyl Anthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, β-chloroanthraquinone, 2-methylthioxanthraquinone, 2-ethylthioxanthraquinone, 2-chlorothioxanthraquinone, 2,4-dimethylthioxanthraquinone, 2,4-diethylthioxanthraquinone, phenyl dimethyl ketone, benzophenone benzyl dimethyl ketone, acetylphenyl dimethyl ketone, p-dimethylaminobenzoate, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, fluorene, triphenylamine, carbazole, benzyl diphenyl One or more of the following: methyl sulfide, tetramethylthiourea monosulfide, ethyl (2,4,6-trimethylbenzoyl)phenylphosphonate, 1-hydroxycyclohexylphenyl ketone, 2-[2-oxo-2-phenylethoxy-ethoxy]-ethyl oxyphenylacetic acid, 2-[2-hydroxy-ethoxy]-ethyl oxyphenylacetic acid, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and phosphine bis(2,4,6-trimethylbenzoyl).

8. A high-residue, low-creep photocurable silicone release agent composition according to claim 6 or 7, characterized in that: The composition also includes a modified photocurable polydimethylsiloxane containing hydroxyl and acrylic functional groups, a solvent, a leveling agent, a defoamer, a coupling agent, and a filler.

9. A high-residue, low-creep photocurable silicone release agent composition according to claim 8, characterized in that: The composition does not contain solvents.

10. A method for preparing a release film, characterized in that: The high residual low creep photocurable silicone release agent composition according to claim 1 is prepared by the following steps: Step S1: Mix components A, B, C, D, and E thoroughly in a dark environment to form a mixture; Step S2: Apply the mixture to the substrate surface using a slit, gravure, or roller coating method; Step S3: After being exposed to UV light, it is cured into a release film.

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