Photocurable adhesive compositions

Abstract

This invention relates to a photocurable adhesive composition comprising: at least one hydroxyl-terminated epoxidized unsaturated first polyolefin with an epoxy equivalent of less than 250 g / eq; at least one hydroxyl-terminated epoxidized unsaturated second polyolefin with an epoxy equivalent of greater than or equal to 250 g / eq; at least one dimer acid-modified epoxy resin; at least one core-shell toughening agent; at least one polyol component; and at least one cationic photoinitiator. The cured product of the photocurable adhesive composition of this invention exhibits excellent acid resistance and elongation properties, thus making it suitable for protecting glass edges during glass thinning processes.

Description

Technical Field

[0001] This invention relates to a photocurable adhesive composition comprising: at least one hydroxyl-terminated epoxidized unsaturated first polyolefin with an epoxy equivalent of less than 250 g / eq; at least one hydroxyl-terminated epoxidized unsaturated second polyolefin with an epoxy equivalent of greater than or equal to 250 g / eq; at least one dimer acid-modified epoxy resin; at least one core-shell toughening agent; at least one polyol component; and at least one cationic photoinitiator. The cured product of the photocurable adhesive composition of this invention exhibits excellent acid resistance and elongation properties, thus making it suitable for protecting glass edges during glass thinning processes. Background Technology

[0002] With the increasing prevalence of electronic devices, there is a growing desire to manufacture them thinner and lighter. One way to achieve this is by thinning the flat panel displays (FPDs) used in these devices. As a major type of FPD, TFT-LCDs typically consist of a cell encapsulating liquid crystals between two pieces of glass. The edges of the TFT-LCD are sealed with a UV-curable adhesive to prevent etching solutions from entering the cell. Because etching solutions often contain strong acids, the glass protected with conventional UV-curable adhesives can only be as thin as approximately 0.3 mm.

[0003] Furthermore, curved or rounded glass is becoming increasingly popular and is a trend for future electronic device displays. Traditional UV-curable adhesives lack sufficient flexibility to protect curved or rounded glass.

[0004] Therefore, there is a need to develop a new type of photocurable adhesive with improved acid resistance and elasticity to better seal and protect glass during the glass thinning process. Summary of the Invention

[0005] This invention relates to a light-curable adhesive composition comprising:

[0006] a) At least one hydroxyl-terminated epoxidized unsaturated first polyolefin with an epoxy equivalent of less than 250 g / eq;

[0007] b) At least one hydroxyl-terminated epoxidized unsaturated second polyolefin with an epoxy equivalent greater than or equal to 250 g / eq;

[0008] c) At least one dimer acid-modified epoxy resin;

[0009] d) At least one core-shell toughening agent;

[0010] e) at least one polyol component; and

[0011] f) At least one cationic photoinitiator;

[0012] The weight ratio between the hydroxyl-terminated epoxidized unsaturated first polyolefin and the hydroxyl-terminated epoxidized unsaturated second polyolefin is 2:5 to 6:5.

[0013] The amount of the core-shell toughening agent is from 3% to 15% by weight based on the total weight of the adhesive composition; and

[0014] The amount of the polyol component is from 1% to 9% by weight based on the total weight of the adhesive composition.

[0015] The present invention also relates to a method for producing the aforementioned photocurable adhesive composition.

[0016] The present invention also relates to the cured product of the aforementioned photocurable adhesive composition. The cured product of the photocurable adhesive composition exhibits excellent acid resistance and elongation properties.

[0017] The present invention also relates to an article for bonding or sealing with a cured product of the aforementioned photocurable adhesive composition. Detailed Implementation

[0018] The invention will be described in more detail in the following paragraphs. Each aspect described may be combined with one or more other aspects unless otherwise expressly indicated. Specifically, any feature indicated as preferred or advantageous may be combined with one or more other features indicated as preferred or advantageous.

[0019] In the context of this invention, unless the context otherwise indicates, the terminology used shall be interpreted in accordance with the following definitions.

[0020] As used herein, the singular forms “a,” “one,” and “the” include both single and plural referents, unless the context clearly indicates otherwise.

[0021] As used herein, the terms “comprising, comprises, comprised of” are synonymous with “including, includes” or “containing, contains” and are inclusive or open-ended, not excluding additional, unlisted components, elements or process steps.

[0022] The list of numerical endpoints includes all numbers and fractions contained within the corresponding range, as well as the listed endpoints.

[0023] All references cited in this specification are incorporated herein by reference.

[0024] Unless otherwise defined, all terms (including technical and scientific terms) used in this invention have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains. Further guidance, including terminology definitions, is provided to better understand the teachings of this invention.

[0025] Hydroxyl-terminated epoxidized unsaturated polyolefins

[0026] The photocurable composition of the present invention comprises at least one hydroxyl-terminated epoxidized unsaturated first polyolefin with an epoxy equivalent of less than 250 g / eq and at least one hydroxyl-terminated epoxidized unsaturated second polyolefin with an epoxy equivalent of greater than or equal to 250 g / eq. The weight ratio between the hydroxyl-terminated epoxidized unsaturated first polyolefin and the hydroxyl-terminated epoxidized unsaturated second polyolefin is 2:5 to 6:5.

[0027] The hydroxyl-terminated epoxidized unsaturated polyolefin of the present invention refers to a polyolefin having at least one non-aromatic double bond, at least one epoxy group, and at least one terminal hydroxyl group per molecule. Preferably, the hydroxyl-terminated epoxidized unsaturated polyolefin contains at least two terminal hydroxyl groups per molecule.

[0028] In some embodiments of the present invention, the hydroxyl-terminated epoxidized unsaturated polyolefin is a hydroxyl-terminated epoxidized polydiene, preferably selected from hydroxyl-terminated epoxidized polyisoprene, hydroxyl-terminated epoxidized polybutadiene, copolymers of hydroxyl-terminated epoxidized isoprene and butadiene, copolymers of hydroxyl-terminated epoxidized butadiene and ethylene, copolymers of hydroxyl-terminated epoxidized butadiene and propylene, and terpolymers of hydroxyl-terminated epoxidized butadiene, ethylene, and propylene. A specific example of a hydroxyl-terminated epoxidized unsaturated polyolefin is shown below:

[0029]

[0030] Where p and q represent the number of repetitions of the epoxide olefin monomer unit in the corresponding []; p and q are integers greater than or equal to 0, and p and q cannot be 0 at the same time; m and n represent the number of repetitions of the unsaturated comonomer unit in the corresponding []; m and n are integers greater than or equal to 0, and m and n cannot be 0 at the same time.

[0031] An example of a commercially available hydroxyl-terminated epoxidized unsaturated first polyolefin is, for example, EPOLEAD PB3600 from Daicel Corporation.

[0032] Examples of commercially available hydroxyl-terminated epoxidized unsaturated second polyolefins are, for example, Poly bd 600E and 605E from Cray Valley.

[0033] In some embodiments of the present invention, the epoxy equivalent of the hydroxyl-terminated epoxidized unsaturated first polyolefin, as measured according to ISO 3001-1997, is preferably 100 to 230 g / eq, more preferably 150 to 200 g / eq.

[0034] In some embodiments of the present invention, the epoxy equivalent of the hydroxyl-terminated epoxidized unsaturated second polyolefin, as measured according to ISO 3001-1997, is preferably 260 to 600 g / eq, more preferably 280 to 380 g / eq.

[0035] In some embodiments of the present invention, the amount of hydroxyl-terminated epoxidized unsaturated first polyolefin is preferably 5% to 20% by weight, more preferably 8% to 14% by weight, based on the total weight of the photocurable adhesive composition.

[0036] In some embodiments of the present invention, the amount of hydroxyl-terminated epoxidized unsaturated second polyolefin is preferably 8% to 25% by weight, more preferably 10% to 20% by weight, based on the total weight of the photocurable adhesive composition.

[0037] In some embodiments of the present invention, when the weight ratio between the hydroxyl-terminated epoxidized unsaturated first polyolefin and the hydroxyl-terminated epoxidized unsaturated second polyolefin is 4:5 to 1:1, the elongation properties of the cured product of the photocurable adhesive composition can be unexpectedly further improved.

[0038] Dimer acid modified epoxy resin

[0039] The photocurable adhesive composition of the present invention comprises at least one dimer acid-modified epoxy resin. The dimer acid-modified epoxy resin of the present invention refers to a resin obtained by reacting at least one carboxyl group in the dimer acid structure with a multifunctional epoxy resin. The dimer acid is a dimer of an unsaturated fatty acid, such as oleic acid, transoleic acid, docosahexaenoic acid, sorbic acid, and linoleic acid. The epoxy resin is not limited and can be any common epoxy resin known in the art.

[0040] Although there is no particular limitation on the epoxy equivalent of dimer acid modified epoxy resin, in some embodiments, the epoxy equivalent of dimer acid modified epoxy resin is preferably 300 to 600 g / eq, as measured according to ISO 3001-1997.

[0041] Examples of commercially available dimer acid-modified epoxy resins are, for example, YD-171 and YD-172 from Kukdo Chemical Co., Ltd.; and jER871 and jER872 from Mitsubish Chemical Corporation.

[0042] In some embodiments of the present invention, the amount of dimer acid-modified epoxy resin is preferably 3% to 25% by weight, more preferably 10% to 20% by weight, based on the total weight of the photocurable adhesive composition.

[0043] Core-shell toughening agent

[0044] The photocurable adhesive composition of the present invention comprises at least one core-shell toughening agent to enhance the elongation properties of the cured product of the photocurable adhesive composition. The core-shell toughening agent used in the present invention can be any core-shell polymer (or core-shell rubber) known in the art. Typically, a core-shell rubber has a core composed of a rubbery polymeric material and a shell grafted onto or crosslinked to the core. The core of the core-shell rubber can be selected from acrylic rubbers, silicone rubbers, and diene rubbers. The shell of the core-shell rubber can be selected from acrylic polymers, acrylic copolymers, styrene polymers, and styrene copolymers. Examples of core-shell rubbers include, but are not limited to, acrylonitrile-butadiene-styrene (ABS), methacrylate-butadiene-styrene (MBS), and methacrylate-acrylonitrile-butadiene-styrene (MABS).

[0045] Examples of commercially available core-shell toughening agents are, for example, MX-550, MX-551 and MX-553, purchased from Kaneka Corporation.

[0046] In some embodiments of the invention, the amount of the core-shell toughening agent is 3% to 15% by weight, preferably 6% to 10% by weight, based on the total weight of the photocurable adhesive composition.

[0047] polyol components

[0048] The photocurable composition of the present invention comprises at least one polyol component. The term "polyol" in this invention refers to a compound containing two or more hydroxyl groups. The polyol component of the present invention can be any common polyol other than the hydroxyl-terminated epoxidized unsaturated polyolefins previously described herein. Examples of polyol components include, but are not limited to, polyether polyols, polyester polyols, and polymeric polyols.

[0049] Examples of commercially available polyol components include, for example, WANOL F-3135 purchased from Wanhua Chemical Group; TEP-330N purchased from the Third Petrochemical Plant of Tianjin Petrochemical Company; GEP-330N purchased from Shanghai Gaoqiao Petrochemical Company; and Voranol 220-110N purchased from Dow.

[0050] In some embodiments of the invention, the amount of the polyol component is from 1% to 9% by weight, preferably 8% by weight, out of 3% by weight, based on the total weight of the photocurable adhesive composition.

[0051] cationic photoinitiator

[0052] The photocurable adhesive composition of the present invention comprises at least one cationic photoinitiator to initiate the polymerization of an epoxy resin. The cationic photoinitiator forms an excited state upon exposure to radiation, and then the excited state decomposes to release free radical cations. These free radical cations react with a hydrogen atom donor to generate a protic acid, which initiates a crosslinking reaction.

[0053] The most commonly used cationic photoinitiators are organohalonium salts, iodonium salts, or sulfonium salts. In some embodiments of the invention, organoiodonium salts or sulfonium salts are preferably incorporated into the photocurable adhesive composition. The anions in these salts typically have low nucleophilicity and include, but are not limited to, SbF6, PF6, AsF6, BF4, B(C6F5)4, or Ga(C6F5)4. Iodonium salts can be selected, for example, from diaryliodonium hexafluorophosphate, diaryliodonium hexafluoroantimonate, diaryliodonium tetra(pentafluorophenyl)borate, 4-octoxyphenylphenyliodonium hexafluoroantimonate, 4-(2-hydroxytetradecyloxyphenyl)phenyliodonium hexafluoroantimonate, and 4-(1-methylethyl)phenyl4-methylphenyliodonium tetra(pentafluorophenyl)borate. The sulfonium salt can be selected from, for example, 4-phenylthiophenyl diphenylsulfonium hexafluoroantimonate, triarylsulfonium hexafluorophosphate, and triarylsulfonium hexafluoroantimonate. The cationic photoinitiator can be used alone or in combination.

[0054] Examples of commercially available cationic photoinitiators include, for instance, Irgacure 290 from BASF; UVI-6976 and 6992 from Nantong Xinnaxi New Materials Co., Ltd.; and UVI 6976 from Dow.

[0055] In some embodiments of the invention, the amount of cationic photoinitiator is from 0.1% to 10% by weight, preferably from 3% to 5% by weight, based on the total weight of the photocurable adhesive composition.

[0056] Optional additives

[0057] The photocurable adhesive composition may also contain optional additives. The selection of suitable additives for use in the photocurable adhesive compositions of the present invention depends on the specific intended use of the photocurable adhesive composition and can be determined by those skilled in the art in a particular case.

[0058] <Reactive epoxy diluent>

[0059] The photocurable compositions of the present invention may optionally contain at least one reactive epoxy diluent that can help regulate the flow properties of the adhesive composition. The reactive epoxy diluents of the present invention refer to compounds containing at least one epoxy group in their molecular structure, and are different from the hydroxyl-terminated epoxidized unsaturated polyolefins and dimer acid-modified epoxy resins previously described in this invention. Preferably, the viscosity of the reactive epoxy diluent is less than 3000 CPS, such as 10 to 2000 CPS, 50 to 1000 CPS, and 100 to 500 CPS, as measured at 25°C according to ASTM D1084-2016. Suitable reactive epoxy diluents include, but are not limited to, aliphatic epoxy resins (such as propylene glycol-diglycidyl ether and pentaerythritol-polyglycidyl ether), alicyclic epoxy resins (such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate and bis(3,4-epoxycyclohexylmethyl)adipate), and heterocyclic epoxy resins (such as triglycidyl isocyanurate).

[0060] Although there is no particular limitation on the epoxy equivalent of reactive epoxy diluents, in some embodiments, as measured according to ISO 3001-1997, the epoxy equivalent of reactive epoxy diluents is preferably less than 250 g / eq, such as 50 g / eq, 100 g / eq and 200 g / eq.

[0061] Examples of commercially available reactive epoxy diluents include, for example, Epodil 749 and 757 from Air Products; Araldite CY179, 184, and 192 from Ciba Specialty Chemicals; AronOxetane OXT 101 from Toagosei Co., Ltd.; and Syna-Epoxy S21, 27, and 28 from Nantong Xinnaxi New Materials Co., Ltd.

[0062] In some embodiments of the invention, the amount of reactive epoxy diluent is from 0% to 60% by weight, preferably from 15% to 50% by weight, based on the total weight of the photocurable adhesive composition.

[0063] <Coupled Agent>

[0064] The photocurable adhesive composition of the present invention may optionally contain at least one coupling agent. The coupling agent of the present invention may be any common coupling agent known in the art. The coupling agent may be selected from silane coupling agents, titanate coupling agents, etc. The coupling agents of the present invention may be used alone or in combination. Examples of silane coupling agents include epoxy-containing alkoxysilanes, such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane. Examples of amino-containing alkoxysilanes include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, and γ-aminopropylmethyldimethoxysilane; and mercapto-containing alkoxysilanes, such as 3-mercaptopropyltrimethoxysilane. Examples of titanate coupling agents include titanium triisostearate isopropoxy.

[0065] Examples of commercially available coupling agents include, for example, KMB403 and KMB603 from Shin-Etsu Chemical; SILQUEST A187 and SILQUEST A1120 from Momentive; KH570 from Dowcorning; and GENIOSIL GF9 from WackerChemie AG.

[0066] In some embodiments of the present invention, the amount of coupling agent is preferably 0% to 5% by weight, more preferably 1% to 3% by weight, based on the total weight of the photocurable adhesive composition.

[0067] <Coloring agent>

[0068] The photocurable adhesive composition of the present invention may optionally contain at least one colorant. Examples of colorants include, but are not limited to, inorganic or organic colorants such as iron oxide, titanium dioxide, bromothymol blue, brilliant blue, phenolphthalein, etc.

[0069] Examples of commercially available colorants are, for example, Stan-Tone 25EPX01Red and Solvent Red 24, purchased from Dintex Dyechem.

[0070] In some embodiments of the present invention, the amount of colorant is preferably 0% to 1% by weight, more preferably 0.1% to 0.2% by weight, based on the total weight of the photocurable adhesive composition.

[0071] Other optional additives that can be used in the light-curable adhesive compositions of the present invention include, but are not limited to, bactericides, fillers, and mixtures thereof.

[0072] In a preferred embodiment, the photocurable adhesive composition comprises:

[0073] (a) at least one hydroxyl-terminated epoxidized unsaturated first polyolefin having an epoxy equivalent of less than 250 g / eq, ranging from 8 wt% to 14 wt%.

[0074] (b) 10% to 20% by weight of at least one hydroxyl-terminated epoxidized unsaturated second polyolefin with an epoxy equivalent greater than or equal to 250 g / eq;

[0075] (c) 10% to 20% by weight of at least one dimer acid modified epoxy resin;

[0076] (d) 6% to 10% by weight of at least one core-shell toughening agent;

[0077] (e) at least one polyol component, ranging from 3% to 8% by weight;

[0078] (f) 3% to 5% by weight of at least one cationic photoinitiator;

[0079] (g) 15% to 50% by weight of at least one reactive epoxy diluent;

[0080] (h) at least one coupling agent, ranging from 1% to 3% by weight; and

[0081] (i) at least one colorant, ranging from 0% by weight to 0.2% by weight;

[0082] The total weight percentage of all components is 100% by weight; and the weight ratio between the hydroxyl-terminated epoxidized unsaturated first polyolefin and the hydroxyl-terminated epoxidized unsaturated second polyolefin is 2:5 to 6:5.

[0083] Those skilled in the art will be able to make appropriate selections among the various components based on the description, representative examples and guidance of the present invention to prepare compositions that achieve the desired effects.

[0084] The photocurable adhesive composition of the present invention can be prepared by uniformly mixing all components together, preferably by the following steps:

[0085] a) Mix all components except the photoinitiator and colorant together to form a premix;

[0086] b) Add the colorant to the premix under continuous stirring; and

[0087] c) Add the photoinitiator to the premix and mix all components under yellow light and vacuum.

[0088] The photocurable adhesive composition of the present invention can be applied to a substrate by a scraper, sprayer, dispenser, or extruder, and allows for UV curing. Suitable substrates include, but are not limited to, metals (such as steel, stainless steel, carbon steel, iron, copper, aluminum, zinc, etc., including alloys thereof), carbon fibers, glass fibers, glass, wood, plastics, woven materials, nonwoven materials, and mixtures thereof.

[0089] In some embodiments of the present invention, the photocurable adhesive composition preferably has a strength of 2000 to 3000 mJ / cm. 2 (such as 2200, 2500 and 2700 mJ / cm) 2 The LED is cured for 365 seconds and irradiated for 10 to 30 seconds (such as 15 seconds and 20 seconds).

[0090] The cured products of the photocurable adhesive compositions exhibit excellent elongation properties and are particularly suitable for protecting curved or rounded glass during glass thinning processes. Furthermore, due to the outstanding acid resistance of the cured products of the photocurable adhesive compositions, glass protected by the cured products of the photocurable adhesive compositions can be thinned to approximately 0.2 mm.

[0091] In some embodiments of the present invention, the elongation at break of the cured product of the photocurable adhesive composition is preferably greater than or equal to 10%, more preferably greater than or equal to 15%, and even more preferably greater than or equal to 20%, as measured according to ASTM D638.

[0092] Example:

[0093] The present invention will now be described and illustrated in further detail with reference to embodiments. These embodiments are intended to help those skilled in the art to better understand and practice the invention, and are not intended to limit the scope of the invention. All figures in the embodiments are based on weight unless otherwise stated.

[0094] Examples 1-16

[0095] The following materials are used in the embodiments.

[0096] YD-171 (dimer acid modified epoxy resin purchased from Kukdo Chemical Co., Ltd);

[0097] MX553 (100nm PBd core-shell rubber (CSP) granules with a 30% concentration in low-viscosity, low-chlorinated cycloaliphatic epoxy resin purchased from Kaneka Corporation);

[0098] EPOLEAD PB3600 (hydroxyl-terminated epoxidized unsaturated polyolefin with an epoxy equivalent of 193 g / eq, purchased from Daicel Corporation);

[0099] Poly bd 605E (hydroxyl-terminated epoxidized unsaturated polyolefin with an epoxy equivalent of 300 g / eq, purchased from Cray Valley);

[0100] Stan-Tone 25EPX01 Red (colorant purchased from PolyOne);

[0101] Voranol 220-110N (a polyol purchased from Dow);

[0102] Syna epoxy 28 (bis(3,4-epoxycyclohexylmethyl) adipate with a viscosity of 500-650 CPS at 25℃, purchased from Nantong Xinnaxi New Material Co., Ltd.);

[0103] Aron Oxetane OXT 101 (3-ethyl-3-hydroxymethyloxetane with a viscosity of 17-22 CPS at 25°C, purchased from Toagosei Co., Ltd);

[0104] SILQUEST A187 (epoxy-functionalized silane purchased from Momentive);

[0105] UVI 6976 (a mixture of triarylsulfonium hexafluoroantimonate in propylene carbonate purchased from Dow) has the following structure:

[0106]

[0107] The photocurable adhesive composition used as an example (Ex.) was prepared by following the steps according to the components and corresponding weight percentages in Table 1:

[0108] a) The dimer acid-modified epoxy resin (YD-171), core-shell toughening agent (MX553), hydroxyl-terminated epoxidized unsaturated polyolefin (EPOLEAD PB3600 and / or Poly bd 605E), polyol component (Voranol 220-110N), reactive epoxy diluent (Syna epoxy 28 and Aron Oxetane OXT 101) and coupling agent (SILQUEST A187) are mixed at 1000 r / min for 30 seconds, and then mixed at 2000 r / min for 60 seconds to form a premix.

[0109] b) Add the colorant (Stan-Tone 25EPX01 Red) to the premix and mix at 1000 r / min for 30 s, then mix at 2000 r / min for 60 s.

[0110] c) Under yellow light and vacuum (vacuum degree controlled at approximately -0.09 MPa), the photoinitiator (UVI 6976) was added to the premix, and all components were mixed at a speed of 1000 r / min for 30 s, and then at a speed of 2000 r / min for 60 s.

[0111] Various tests were performed on the light-curable adhesive samples, and the results are recorded in Tables 2 and 3.

[0112] Table 1a. Photocurable adhesive compositions

[0113]

[0114] Table 1b. Photocurable adhesive compositions

[0115]

[0116] Test methods

[0117] <Acid Resistance>

[0118] A photocurable adhesive sample was coated onto a glass substrate to form a wet film with a thickness of approximately 200 μm, and the glass coated with the wet film was exposed to Hg-UV light (786 mJ / cm²). 2 Let it solidify in 20 seconds.

[0119] A glass substrate coated with a thin film was immersed in a sulfuric acid solution (35wt%) for 24 hours at 23°C and 50% humidity.

[0120] The acid resistance of the film is evaluated as follows:

[0121] If the film shows no corrosion, no bubbles, no color change, and can be easily peeled off continuously from the glass without cracking, the acid resistance of the cured light-curable adhesive sample is rated as "qualified"; and

[0122] If the film shows signs of corrosion, bubbles, discoloration, or cracking during peeling, the acid resistance of the cured light-curable adhesive sample will be rated as "unacceptable".

[0123] <Elongation Properties>

[0124] The following steps were used to cure and test the light-curable adhesive sample:

[0125] a) Place the mold (size: 200×200×1mm) on a horizontally placed glass substrate;

[0126] b) Fill the mold with a sample of photocurable adhesive to form a wet film with a thickness of 1 mm;

[0127] c) Place the second glass substrate on the mold to encapsulate the wet film between the two glass substrates;

[0128] d) Using Hg-UV light (786 mJ / cm) 2 Irradiate the encapsulated wet film for 20 seconds;

[0129] e) Invert the encapsulated wet film and then expose it to Hg-UV light (786mj / cm²). 2 Irradiate the encapsulated wet film for 20 seconds;

[0130] f) Turn the encapsulated wet film over again and expose it to Hg-UV light (786mj / cm²). 2 Irradiate the encapsulated wet film for 20 seconds to form a dry film;

[0131] g) Prepare a sample membrane from a dry membrane according to ASTM D638;

[0132] h) Before testing, store the sample membrane at 23°C and 50% humidity for 24 hours; and

[0133] i) Measure the elongation at break of the sample film according to ASTM D638.

[0134] Test Results

[0135] Table 2a. Acid resistance

[0136] Ex1 Ex2 Ex3 Ex4 Ex5 Ex6 Ex7 Ex8 qualified qualified qualified qualified qualified qualified qualified qualified

[0137] Table 2b. Acid Resistance

[0138] Ex9 Ex.10 Ex.11 Ex.12 Ex.13 Ex.14 Ex.15 Ex.16 Unqualified qualified qualified qualified qualified qualified qualified Unqualified

[0139] The acid resistance of the cured photocurable adhesive samples is recorded in Tables 2a and 2b. The cured photocurable adhesive samples exhibited poor acid resistance when the hydroxyl-terminated epoxidized unsaturated first polyolefin (EPOLEAD PB3600) was absent from the photocurable adhesive composition sample or when an excessive amount of polyol component (Voranol 220-110N) was added to the photocurable adhesive composition sample.

[0140] Table 3a. Elongation properties

[0141] Elongation at break Ex1 Ex2 Ex3 Ex4 Ex5 Ex6 Ex7 Ex8 percentage(%) 14.7 13.1 25.2 12.2 15.8 25.7 12.3 24.6

[0142] Table 3b. Elongation Properties

[0143] Elongation at break Ex9 Ex.10 Ex.11 Ex.12 Ex.13 Ex.14 Ex.15 Ex.16 percentage(%) 23.6 5.2 9.8 3.6 6.0 8.2 5.6 15.3

[0144] The elongation properties of the cured photocurable adhesive samples are recorded in Tables 3a and 3b. The elongation properties of the cured photocurable adhesive samples were poor when the weight ratio between the hydroxyl-terminated epoxidized unsaturated first polyolefin and the hydroxyl-terminated epoxidized unsaturated second polyolefin was not in the range of 2:5 to 6:5, or when the polyol component or the dimer acid-modified epoxy resin (YD-171) was missing from the photocurable adhesive composition samples.

Claims

1. A photocurable adhesive composition comprising: a) At least one hydroxyl-terminated epoxidized unsaturated first polyolefin with an epoxy equivalent of less than 250 g / eq; b) At least one hydroxyl-terminated epoxidized unsaturated second polyolefin with an epoxy equivalent greater than or equal to 250 g / eq; c) At least one dimer acid-modified epoxy resin; d) At least one core-shell toughening agent; e) at least one polyol component; and f) At least one cationic photoinitiator; in The weight ratio between the hydroxyl-terminated epoxidized unsaturated first polyolefin and the hydroxyl-terminated epoxidized unsaturated second polyolefin is 2:5 to 6:

5. The amount of the core-shell toughening agent is from 3% to 15% by weight based on the total weight of the adhesive composition; and The amount of the polyol component is from 1% to 9% by weight based on the total weight of the adhesive composition.

2. The photocurable adhesive composition according to claim 1, wherein each molecule of the hydroxyl-terminated epoxidized unsaturated first polyolefin has two terminal hydroxyl groups.

3. The photocurable adhesive composition according to claim 1 or 2, wherein the hydroxyl-terminated epoxidized unsaturated second polyolefin has two terminal hydroxyl groups per molecule.

4. The photocurable adhesive composition according to claim 1 or 2, wherein the epoxy equivalent of the hydroxyl-terminated epoxidized unsaturated first polyolefin is 100 to 230 g / eq.

5. The photocurable adhesive composition according to claim 1 or 2, wherein the epoxy equivalent of the hydroxyl-terminated epoxidized unsaturated second polyolefin is 260 to 600 g / eq.

6. The photocurable adhesive composition according to claim 1 or 2, wherein the hydroxyl-terminated epoxidized unsaturated first and second polyolefins are both hydroxyl-terminated epoxidized polydies.

7. The photocurable adhesive composition according to claim 1 or 2, wherein the amount of the hydroxyl-terminated epoxidized unsaturated first polyolefin is from 5% to 20% by weight based on the total weight of the adhesive composition.

8. The photocurable adhesive composition according to claim 1 or 2, wherein the amount of the hydroxyl-terminated epoxidized unsaturated second polyolefin is from 8% to 25% by weight based on the total weight of the adhesive composition.

9. The photocurable adhesive composition according to claim 1 or 2, wherein the amount of the polyol component is from 3% to 8% by weight based on the total weight of the adhesive composition.

10. The photocurable adhesive composition according to claim 1 or 2, wherein the weight ratio between the hydroxyl-terminated epoxidized unsaturated first polyolefin and the hydroxyl-terminated epoxidized unsaturated second polyolefin is 4:5 to 1:

1.

11. The photocurable adhesive composition according to claim 1 or 2, wherein the cationic photoinitiator is selected from organohalonium salts, organoiodonium salts, organosulfonium salts, or any combination thereof.

12. The photocurable adhesive composition according to claim 1 or 2, comprising: (a) 8% to 14% by weight of at least one hydroxyl-terminated epoxidized unsaturated first polyolefin with an epoxy equivalent of less than 250 g / eq; (b) 10% to 20% by weight of at least one hydroxyl-terminated epoxidized unsaturated second polyolefin with an epoxy equivalent greater than or equal to 250 g / eq; (c) 10% to 20% by weight of at least one dimer acid-modified epoxy resin; (d) 6% to 10% by weight of at least one core-shell toughening agent; (e) at least one polyol component, ranging from 3% to 8% by weight; (f) 3% to 5% by weight of at least one cationic photoinitiator; (g) 15% to 50% by weight of at least one reactive epoxy diluent; (h) at least one coupling agent, ranging from 1% to 3% by weight; and (i) at least one colorant, from 0% by weight to 0.2% by weight; in The total weight percentage of all components is 100% by weight; and The weight ratio between the hydroxyl-terminated epoxidized unsaturated first polyolefin and the hydroxyl-terminated epoxidized unsaturated second polyolefin is 2:5 to 6:

5.

13. A method for producing a photocurable adhesive composition according to any one of claims 1 to 12, comprising the following steps: a) Mix all components except the photoinitiator and colorant together to form a premix; b) Add the colorant to the premix while continuously stirring; as well as c) Add the photoinitiator to the premix and mix all components under yellow light and vacuum.

14. The cured product of the photocurable adhesive composition according to any one of claims 1 to 12.

15. An article coated or bonded with a cured product of a photocurable adhesive composition according to any one of claims 1 to 12.

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