Aldehyde-removing coating, uv aldehyde-removing resin and preparation materials and methods thereof

Abstract

This invention discloses a formaldehyde-removing coating, a UV formaldehyde-removing resin, its preparation raw materials, and a preparation method thereof. The UV formaldehyde-removing resin contains a siloxane structure and an active methylene structure with formaldehyde-removing function or a cyclovinylene structure containing a secondary amine group. The preparation method of the UV formaldehyde-removing resin includes: mixing a first raw material with a siloxane structure with a second raw material, the second raw material comprising an active methylene group with formaldehyde-removing function and / or a cyclovinylene containing a secondary amine group; introducing the active methylene group with formaldehyde-removing function or the cyclovinylene containing a secondary amine group into the oligomer resin molecular chain with photocuring function via transesterification or isocyanate functional groups to obtain the UV formaldehyde-removing resin. The formaldehyde-removing coating, UV formaldehyde-removing resin, its preparation raw materials, and the preparation method proposed in this invention can improve the formaldehyde removal efficiency of UV formaldehyde-removing resin.

Description

Technical Field

[0001] This invention belongs to the technical field of interior decoration materials, and relates to a UV resin, particularly to a formaldehyde-removing coating, a UV formaldehyde-removing resin, its preparation raw materials and preparation method. Background Technology

[0002] UV curing technology is widely used in industries such as coatings, printing, and adhesives due to its advantages of fast curing speed, energy saving, environmental protection, and high production efficiency. Its production and application principle involves using ultraviolet light to excite internal photoinitiators to generate free radicals, which instantly trigger a photochemical free radical polymerization reaction, initiating free radical chain polymerization reactions of monomers, prepolymers, and other active substances.

[0003] Formaldehyde, as one of the main air pollutants in indoor decoration, has been classified as a Group 1 carcinogen. Formaldehyde has an irritating and suffocating odor and is widely found in various synthetic building materials, latex paints, plywood, decorative materials, insulation materials, synthetic leather, rubber and plastic products. The formaldehyde concentration exceeding the standard is especially high in newly renovated houses or places.

[0004] Currently, methods for removing indoor formaldehyde mainly include ventilation, plant absorption, physical adsorption using porous materials, photocatalysis, and chemical reactions. Ventilation utilizes opening doors and windows or using ventilation fans to exchange air and reduce formaldehyde concentration. While simple and easy to implement, formaldehyde has a long latency period and is slowly released; when the space is closed again, the formaldehyde concentration will increase over time. Plant absorption primarily uses plants such as spider plants, snake plants, and ivy to absorb formaldehyde and reduce its concentration to some extent. This method is simple and easy to use, but its air purification efficiency is low and the effect is not ideal. Physical adsorption mainly utilizes the porous structure and high specific surface area of ​​materials to physically adsorb formaldehyde. These materials include activated carbon, diatomaceous earth, bentonite, and molecular sieves. While this method can remove formaldehyde, physical adsorption is a dynamic and reversible process; under certain conditions, desorption can occur, causing a secondary release of formaldehyde and re-polluting the environment. Photocatalytic methods utilize photocatalytic nanomaterials (such as TiO2, ZnO, ZnS, MnO2, etc.) to undergo photocatalytic reactions under light irradiation, generating active free radicals that decompose formaldehyde into carbon dioxide and water. While this method is energy-efficient and highly effective, its practical application is limited by the cost of nanomaterials and stringent reaction conditions (generally requiring ultraviolet light or sunlight). Chemical formaldehyde removal methods primarily utilize substances with specific functional groups to react chemically with formaldehyde, thereby reducing its concentration. These specific functional groups that react with formaldehyde include reactive amine compounds and compounds containing active methylene groups. Specifically, the active amine functional groups that react with formaldehyde refer to structural units such as terminal amine groups, amide groups, urea groups, and cycloethylene urea containing primary or secondary amine groups. These units undergo nucleophilic addition reactions between the lone pair electrons of the nitrogen atom on the amine group and the carbon atom in the formaldehyde molecule to generate hydroxymethyl groups. Further dehydration condensation of the hydroxymethyl group eliminates formaldehyde. The dehydration reaction of the cycloethylene urea structure containing a secondary amine group with formaldehyde is an irreversible reaction. Another type of characteristic functional group that reacts with formaldehyde is the active methylene structural unit with double α-hydrogen atoms (an α-carbon atom connected to two electron-withdrawing groups). This unit can capture formaldehyde even at low concentrations, and the reaction is irreversible.

[0005] Although there are many existing formaldehyde removal solutions, their effectiveness is not ideal due to low efficiency, poor stability, harsh reaction conditions, and inconvenience.

[0006] In view of this, there is an urgent need to design a new formaldehyde removal solution to overcome at least some of the aforementioned shortcomings of existing formaldehyde removal solutions. Summary of the Invention

[0007] This invention provides a formaldehyde-removing coating, a UV formaldehyde-removing resin, its raw materials and preparation method, which can improve the formaldehyde removal efficiency of the UV formaldehyde-removing resin, ensure a stable formaldehyde removal process, and prevent secondary formaldehyde release.

[0008] To solve the above-mentioned technical problems, according to one aspect of the present invention, the following technical solution is adopted:

[0009] A UV formaldehyde removal resin, wherein the general formula of the UV formaldehyde removal resin contains, in addition to carbon-carbon double bonds, a siloxane structure, and an active methylene structure with formaldehyde removal function or a cyclovinyl urea structure containing a secondary amine group.

[0010] As one embodiment of the present invention, the UV formaldehyde removal resin includes an active methylene structure with formaldehyde removal function or an oligomer of cycloethylene urea containing a secondary amine group.

[0011] The structure of the reactive methylene group with formaldehyde removal function is as follows:

[0012]

[0013] The structure of a cyclovinyl urea containing a secondary amine group is as follows:

[0014]

[0015] Among them, R2 and R3 are the remaining segments of the photocurable formaldehyde-removing resin;

[0016] The siloxane structure is as follows:

[0017]

[0018] The UV formaldehyde removal resin includes a structure as shown in general formula I, general formula II, general formula III, or general formula IV.

[0019] General formula I is as follows:

[0020]

[0021] In general formula I, CR1=CH2 is -CH=CH2 or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25;

[0022] Formula II is as follows:

[0023]

[0024] In general formula II, CR1=CH2 is -CH=CH2 or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25;

[0025] Formula III is as follows:

[0026]

[0027] In general formula III, m and n are independent integers from 1 to 25;

[0028] Formula IV is as follows:

[0029]

[0030] In general formula IV, m and n are independent integers from 1 to 25.

[0031] As one embodiment of the present invention, the UV formaldehyde removal resin includes a structure that can participate in the photocuring reaction, and the structure that can participate in the photocuring reaction includes one or a combination of at least two of vinyl, acrylate, and methacrylate structural units.

[0032] By introducing active methylene groups or cyclovinyl urea containing secondary amine groups into the molecular chain of an oligomer resin with photocuring function through transesterification or isocyanate functional groups, a UV-curing resin is obtained.

[0033] According to another aspect of the present invention, the following technical solution is adopted: a formaldehyde-removing coating, wherein the formaldehyde-removing coating comprises the above-mentioned UV formaldehyde-removing resin.

[0034] According to another aspect of the present invention, the following technical solution is adopted: a raw material for preparing a UV formaldehyde removal resin, the raw material comprising: a first raw material having a siloxane structure and a second raw material; the second raw material comprising an active methylene group having formaldehyde removal function and / or a cycloethylene urea containing a secondary amine group;

[0035] By introducing an active methylene group or a cyclovinyl urea containing a secondary amine group into the molecular chain of an oligomer resin with photocuring function through transesterification or isocyanate functional group, a UV-curing resin is obtained.

[0036] In addition to carbon-carbon double bonds, the general formula of the UV formaldehyde removal resin also contains a siloxane structure, an active methylene structure with formaldehyde removal function, or a cyclovinyl urea structure containing a secondary amine group.

[0037] As one embodiment of the present invention, the first raw material includes hydroxyaminosiloxane of formula (1) and / or methylaminosiloxane of formula (2) and / or hydroxyvinylsiloxane of formula (3), and the obtained UV formaldehyde removal resin has the structure shown in general formula I and / or general formula II and / or general formula III and / or general formula IV.

[0038]

[0039] In equations (1) and (2), R is monoammonium-CH2CH2CH2NH2 or diammonium-CH2CH2CH2NHCH2CH2NH2 or triammonium-C3H6NHC2H4NHC2H4NH2, and m and n are independent integers from 1 to 25.

[0040]

[0041] In equation (3), m and n are independent integers from 1 to 25;

[0042] General formula I is as follows:

[0043]

[0044] In general formula I, CR1=CH2 is -CH=CH2 or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25;

[0045] Formula II is as follows:

[0046]

[0047] In general formula II, CR1=CH2 is -CH=CH2 or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25;

[0048] Formula III is as follows:

[0049]

[0050] In general formula III, m and n are independent integers from 1 to 25;

[0051] Formula IV is as follows:

[0052]

[0053] In general formula IV, m and n are independent integers from 1 to 25.

[0054] According to another aspect of the present invention, the following technical solution is adopted: a method for preparing a UV formaldehyde-removing resin, the preparation method comprising:

[0055] A first raw material having a siloxane structure is mixed with a second raw material, wherein the second raw material includes an active methylene group with aldehyde removal function and / or a cycloethylene urea containing a secondary amine group;

[0056] An active methylene group or a cyclovinyl urea containing a secondary amine group with aldehyde removal function is introduced into the molecular chain of an oligomer resin with photocuring function via transesterification or isocyanate functional group to obtain a UV aldehyde removal resin.

[0057] The general formula of the UV formaldehyde removal resin contains a siloxane structure, as well as an active methylene structure with formaldehyde removal function or a cyclovinyl urea structure containing a secondary amine group.

[0058] As one embodiment of the present invention, the first raw material includes hydroxyaminosiloxane of formula (1) and / or methylaminosiloxane of formula (2) and / or hydroxyvinylsiloxane of formula (3), and the obtained UV formaldehyde removal resin has the structure shown in general formula I and / or general formula II and / or general formula III and / or general formula IV.

[0059]

[0060] In equations (1) and (2), R is monoammonium-CH2CH2CH2NH2 or diammonium-CH2CH2CH2NHCH2CH2NH2 or triammonium-C3H6NHC2H4NHC2H4NH2, and m and n are independent integers from 1 to 25.

[0061]

[0062] In equation (3), m and n are independent integers from 1 to 25;

[0063] General formula I is as follows:

[0064]

[0065] In general formula I, CR1=CH2 is -CH=CH2 or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25;

[0066] Formula II is as follows:

[0067]

[0068] In general formula II, CR1=CH2 is -CH=CH2 or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25;

[0069] Formula III is as follows:

[0070]

[0071] In general formula III, m and n are independent integers from 1 to 25;

[0072] Formula IV is as follows:

[0073]

[0074] In general formula IV, m and n are independent integers from 1 to 25.

[0075] As one embodiment of the present invention, the -CR1=CH2 structural unit is introduced into the siloxane molecular chain through a monomer or oligomer with dual curing function;

[0076] The monomer or oligomer with dual curing function must contain carbon-carbon double bonds and have epoxy or isocyanate functional groups; the carbon-carbon double bond functional group for photocuring is introduced by reacting epoxy or isocyanate groups with amine groups; the monomer or oligomer with dual curing function includes at least one of ethyl isocyanate acrylate, isocyanoethyl methacrylate, allyl isocyanate, and glycidyl methacrylate.

[0077] When reacting with dual-curing functional monomers or hydroxyvinylsiloxanes, a polymerization inhibitor is added to prevent polymerization failure during product preparation and subsequent storage. The polymerization inhibitor includes at least one of p-methoxyphenol, 2,4,6-trinitrophenol, 1,4-benzoquinone, hydroquinone, and 2,6-di-tert-butyl-p-cresol. The amount of polymerization inhibitor added is 0.01-0.3% of the total mass of the dual-curing monomers or hydroxyvinylsiloxanes.

[0078] The structures of monomers with active methylene groups that participate in hydroxyl-containing siloxane ester exchange are as follows:

[0079]

[0080] Wherein, R4 is one of -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, that is, the monomer structure with an active methylene group includes one or a combination of at least two of methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, and tert-butyl acetoacetate.

[0081] In general formulas I, II, and IV, the ethylene urea structural unit containing a secondary amine group is bridged with the amine or hydroxyl group in the siloxane via a diisocyanate reaction, and the ethylene urea structure is as follows:

[0082]

[0083] The diisocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

[0084] As one embodiment of the present invention, the preparation method further includes:

[0085] Add the hydroxyaminosiloxane of formula (1) or the hydroxyvinylsiloxane of formula (3), a monomer containing an active methylene group, and a catalyst to the reactor, and carry out transesterification under an inert gas. The reaction ends when the residual amount of the active methylene monomer is less than 0.1%, thereby introducing the active methylene structure into the siloxane chain segment.

[0086] The catalyst is one or a mixture of several of p-toluenesulfonic acid, tetrabutyl titanate, and dibutyltin dilaurate, and the amount of catalyst added is 0.05-1% of the total mass of the active methylene monomer and aminosiloxane or hydroxyvinylsiloxane.

[0087] The specific transesterification process is as follows: Under the protection of inert gas, the materials fed in proportion are stirred and heated to 100-130℃ and reacted for 3-5 hours. The temperature is then increased to 130-180℃ to continue the reaction. The residual amount of active methylene monomer is tested, and the reaction is stopped when its content is less than 0.1%.

[0088] Alternatively, the preparation method further includes:

[0089] The process of introducing a cyclovinylurea structural unit containing a secondary amine group into an aminosiloxane or a hydroxyvinylsiloxane includes: for aminosiloxanes, the introduction is achieved by reacting a diisocyanate with the amine group or the hydroxyl group formed after the epoxy group in the aminosiloxane ring-opening to form an isocyanate end cap, followed by the addition of cyclovinylurea; for hydroxyvinylsiloxanes, the process involves reacting a diisocyanate with the terminal hydroxyl group to form an isocyanate end cap, followed by the addition of cyclovinylurea.

[0090] The endpoint of the reaction between the epoxy group and the amine group is determined by the disappearance of the characteristic absorption peak in the infrared spectrum of the reaction solution.

[0091] The reaction temperature of amino groups with diisocyanates is 40-60℃, the reaction temperature of hydroxyl groups with diisocyanates is 60-120℃, and the reaction temperature of cycloethylene urea with isocyanate functional groups is 100-120℃. The reaction endpoint is determined by the NCO content or the disappearance of characteristic absorption peaks in the infrared spectrum of the reaction solution.

[0092] The beneficial effects of this invention are as follows: the formaldehyde-removing coating, UV formaldehyde-removing resin, and their preparation raw materials and preparation methods proposed in this invention can improve the formaldehyde removal efficiency of UV formaldehyde-removing resin.

[0093] The UV formaldehyde removal resin prepared by this invention can be used to formulate UV curing products, especially UV coating products. This UV formaldehyde removal resin is modified with methylsiloxane. By utilizing the low surface tension and easy migration and enrichment of methylsiloxane to the surface, the utilization rate of the formaldehyde removal monomer is improved, and the formaldehyde removal monomer can maximize its function of purifying formaldehyde.

[0094] Furthermore, the formaldehyde removal mechanism of the formaldehyde removal resin in this invention utilizes the active methylene group or the cycloethylene urea structure containing a secondary amine group that reacts irreversibly with formaldehyde. It does not require harsh conditions such as light exposure, the formaldehyde removal process is stable, and there is no problem of secondary formaldehyde release. The formaldehyde removal product is a small molecule that only generates water. The formaldehyde removal process is environmentally friendly and safe, achieving the purpose of purifying the air environment. Attached Figure Description

[0095] Figure 1 This is a flowchart of a method for preparing UV formaldehyde-removing resin in one embodiment of the present invention. Detailed Implementation

[0096] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0097] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0098] The description in this section pertains to only a few typical embodiments, and the present invention is not limited to the scope of the embodiments described. Substitution of identical or similar prior art methods with some technical features in the embodiments is also within the scope of the description and protection of this invention.

[0099] The steps described in the various embodiments in the specification are for illustrative purposes only, and the implementation of this application is not limited by the order of the steps.

[0100] This invention discloses a UV formaldehyde removal resin, wherein the general formula of the UV formaldehyde removal resin contains, in addition to carbon-carbon double bonds, a siloxane structure, and an active methylene structure with formaldehyde removal function or a cyclovinyl urea structure containing a secondary amine group.

[0101] In addition, the UV formaldehyde removal resin may include structures that can participate in the photocuring reaction, and the structures that can participate in the photocuring reaction may include one or a combination of at least two of the following structural units: vinyl, acrylate, and methacrylate.

[0102] In one embodiment of the present invention, the UV formaldehyde-removing resin comprises an active methylene structure with formaldehyde-removing function or an oligomer of cycloethylene urea containing a secondary amine group; the structure of the active methylene group with formaldehyde-removing function is as follows:

[0103]

[0104] The structure of a cyclovinyl urea containing a secondary amine group is as follows:

[0105]

[0106] Among them, R2 and R3 are the remaining segments of the photocurable formaldehyde-removing resin;

[0107] The siloxane structure is as follows:

[0108]

[0109] In one embodiment, the UV formaldehyde removal resin comprises a structure as shown in formula I, II, III, or IV.

[0110]

[0111] In general formula I, CR1=CH2 is -CH=CH2 or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25;

[0112]

[0113] In general formula II, CR1=CH2 is -CH=CH2 or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25;

[0114]

[0115] In general formula III, m and n are independent integers from 1 to 25;

[0116]

[0117] In general formula IV, m and n are independent integers from 1 to 25;

[0118] The above general formula contains an active methylene group that can react irreversibly with formaldehyde or a cyclovinylurea structure containing a secondary amine group, as shown below:

[0119]

[0120] R2 and R3 are the remaining segments of the photocurable formaldehyde-removing resin.

[0121] The above general formula contains methylsiloxane segments, as shown below:

[0122]

[0123] In general formulas I, II, III, and IV, the structures that can participate in the photocuring reaction are one or more combinations of vinyl, acrylate, and methacrylate structural units, as shown below:

[0124]

[0125] This invention also discloses a raw material for preparing a UV formaldehyde-removing resin, comprising: a first raw material having a siloxane structure and a second raw material; the second raw material comprises an active methylene group with formaldehyde-removing function and / or a cycloethylene urea containing a secondary amine group. The active methylene group with formaldehyde-removing function or the cycloethylene urea containing a secondary amine group is introduced into the molecular chain of an oligomer resin with photocuring function via transesterification or isocyanate functional groups to obtain the UV formaldehyde-removing resin. The general formula of the UV formaldehyde-removing resin, in addition to containing a carbon-carbon double bond, also contains a siloxane structure, and an active methylene group with formaldehyde-removing function or a cycloethylene urea structure containing a secondary amine group.

[0126] In one embodiment of the present invention, the first raw material includes hydroxyaminosiloxane of formula (1) and / or methylaminosiloxane of formula (2) and / or hydroxyvinylsiloxane of formula (3), and the obtained UV formaldehyde removal resin has the structure shown in general formula I and / or general formula II and / or general formula III and / or general formula IV.

[0127]

[0128] In equations (1) and (2), R is monoammonium-CH2CH2CH2NH2 or diammonium-CH2CH2CH2NHCH2CH2NH2 or triammonium-C3H6NHC2H4NHC2H4NH2, and m and n are independent integers from 1 to 25.

[0129]

[0130] In equation (3), m and n are independent integers from 1 to 25;

[0131] General formula I is as follows:

[0132]

[0133] In general formula I, CR1=CH2 is -CH=CH2 or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25;

[0134] Formula II is as follows:

[0135]

[0136] In general formula II, CR1=CH2 is -CH=CH2 or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25;

[0137] Formula III is as follows:

[0138]

[0139] In general formula III, m and n are independent integers from 1 to 25;

[0140] Formula IV is as follows:

[0141]

[0142] In general formula IV, m and n are independent integers from 1 to 25.

[0143] This invention also discloses a method for preparing a UV-cured formaldehyde-removing resin. Figure 1 This is a flowchart of a method for preparing UV formaldehyde-removing resin according to an embodiment of the present invention; the preparation method includes:

[0144] A first raw material having a siloxane structure is mixed with a second raw material, wherein the second raw material includes an active methylene group with aldehyde removal function and / or a cycloethylene urea containing a secondary amine group;

[0145] An active methylene group or a cyclovinyl urea containing a secondary amine group with aldehyde removal function is introduced into the molecular chain of an oligomer resin with photocuring function via transesterification or isocyanate functional group to obtain a UV aldehyde removal resin.

[0146] The general formula of the UV formaldehyde removal resin contains a siloxane structure, as well as an active methylene structure with formaldehyde removal function or a cyclovinyl urea structure containing a secondary amine group.

[0147] In one embodiment of the present invention, the first raw material includes hydroxyaminosiloxane of formula (1) and / or methylaminosiloxane of formula (2) and / or hydroxyvinylsiloxane of formula (3) to introduce active methylene or cyclovinyl urea containing secondary amine group with aldehyde removal function into the oligomer resin molecular chain with photocuring function through transesterification or diisocyanate.

[0148]

[0149] In equations (1) and (2), R is -CH2CH2CH2NH2 (monoammonia) or -CH2CH2CH2NHCH2CH2NH2 (diammonia) or C3H6NHC2H4NHC2H4NH2 (triammonia), and m and n are independent integers from 1 to 25;

[0150]

[0151] In equation (3), m and n are independent integers from 1 to 25.

[0152] The -CR1=CH2 structural unit shown in General Formula I and General Formula II can be introduced into the siloxane molecular chain by monomers or oligomers with dual curing functions. Such monomers or oligomers with dual curing functions must contain carbon-carbon double bonds and epoxy or isocyanate functional groups. Carbon-carbon double bond functional groups that can undergo photocuring are introduced by reacting epoxy or isocyanate groups with amine groups. Such monomers or oligomers with dual curing functions include ethyl isocyanate acrylate, isocyanoethyl methacrylate, allyl isocyanate, glycidyl methacrylate, etc.

[0153] Formulas (1) and (2) do not possess the carbon-carbon double bond functional group characteristic of UV curing structure, therefore, it is necessary to introduce carbon-carbon double bonds through monomers or oligomers with dual curing properties; while Formula (3) has carbon-carbon double bonds and already possesses UV curing function, therefore, only the formaldehyde removal structural unit needs to be introduced in Formula (3) to achieve UV curing and formaldehyde removal functions. In addition, for Formulas (1) and (2), since Formula 1 has hydroxyl groups, an active methylene structure with formaldehyde removal function can be introduced through transesterification; for the side group R, Formulas (1) and (2) are similar, both being monoamine, diamine, and triamine structures containing amine functional groups. This structure introduces the carbon-carbon double bond UV curing structural unit into Formulas (1) and (2) by using a dual curing monomer or oligomer containing epoxy functional groups. Furthermore, hydroxyl functional groups are generated during the reaction of epoxy and amine groups. These hydroxyl groups are then reacted with diisocyanate to form isocyanate functional groups for end-capping. The remaining isocyanate functional groups react with vinylene urea to introduce vinylene urea structural units with formaldehyde removal function. Through the above reaction process, carbon-carbon double bonds and formaldehyde removal structural units required for UV curing are introduced into formulas (1) and (2). General formula I is prepared by reacting formula (1); general formula II is prepared by reacting formula (2); and general formulas III and IV are prepared by reacting formula (3).

[0154] When adding dual-curing functional monomers or hydroxyvinylsiloxanes to the reaction, polymerization inhibitors need to be added to prevent polymerization failure during product preparation and subsequent storage. The polymerization inhibitors include: p-methoxyphenol, 2,4,6-trinitrophenol, 1,4-benzoquinone, hydroquinone, 2,6-di-tert-butyl-p-cresol, etc., and the amount added is 0.01-0.3% of the total mass of the dual-curing monomers or hydroxyvinylsiloxanes.

[0155] In one embodiment of the present invention, the structure of the active methylene monomer participating in the transesterification of hydroxyl-containing siloxanes is as follows:

[0156]

[0157] R4 is one of -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, namely methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, tert-butyl acetoacetate, and during transesterification, it is one of these or a combination of at least two of them.

[0158] An active methylene structure with aldehyde removal function is introduced into the siloxane molecular chain using an ester exchange method. During preparation, aminosiloxane or hydroxyvinylsiloxane with structures shown in formula (1) and formula (3), monomers containing active methylene groups, and catalysts are added to the reactor. Ester exchange is carried out under an inert gas atmosphere to remove small molecule alkyl alcohols (R4-OH). The reaction ends when the residual amount of active methylene monomer is less than 0.1% of the total feed weight. The reaction endpoint is quantitatively confirmed by gas chromatography analysis to determine the content of residual active methylene monomer in the reaction solution, thereby introducing the active methylene structure into the siloxane molecular chain.

[0159] In this invention, the catalyst used for transesterification is one or a mixture of several of p-toluenesulfonic acid, tetrabutyl titanate, and dibutyltin dilaurate. The amount of catalyst added is 0.05-1% of the total mass of the active methylene monomer and aminosiloxane or hydroxyvinylsiloxane. The inert gas can be nitrogen. In one embodiment, the transesterification process is as follows: under inert gas protection, the materials added in proportion are stirred and heated to 100-130°C, reacted for 3-5 hours, and then the temperature is increased to 130-180°C to continue the reaction. The residual amount of active methylene monomer is tested, and the reaction is stopped when its content is less than 0.1%. In addition, the preparation method of this invention also includes a process of cooling down or continuing subsequent reactions after stopping the reaction following transesterification.

[0160] In one embodiment of the present invention, the method for introducing a cyclovinyl urea structural unit containing a secondary amine group into an aminosiloxane or a hydroxyvinyl siloxane is as follows: For aminosiloxanes, the introduction is achieved by reacting a diisocyanate with the hydroxyl group formed after the amino or epoxy group in the aminosiloxane ring-opening process to form an isocyanate end cap, followed by the addition of cyclovinyl urea; for hydroxyvinyl siloxanes, the isocyanate end cap can be formed by reacting a diisocyanate with a terminal hydroxyl group, followed by the addition of cyclovinyl urea.

[0161] The diisocyanates used in this invention include toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, etc. In the reaction of the epoxy-based dual-cured monomer with carbon-carbon double bonds with aminosiloxane, the endpoint of the reaction between the epoxy and amino groups is determined by the disappearance of the absorption peak near 908 cm⁻¹ in the infrared spectrum of the reaction solution.

[0162] The reaction temperature of amino groups with epoxy monomers is 50-90℃, the reaction temperature of amino groups with diisocyanates is 40-60℃, the reaction temperature of hydroxyl groups with diisocyanates is 60-120℃, and the reaction temperature of cycloethylene urea with isocyanate functional groups is 100-120℃. The reaction endpoint of hydroxyl or amino groups with isocyanates is determined by the NCO content, and the final reaction endpoint of cycloethylene urea with isocyanate functional groups is determined by the disappearance of the absorption peak near 2270 cm-1 in the infrared spectrum of the reaction solution.

[0163] The typical, but not limiting, use of the UV formaldehyde-removing resin described in this invention is for purifying and removing formaldehyde. The specific method of use is as follows: the prepared UV formaldehyde-removing resin is added to a UV coating, mixed evenly, and then applied. After UV curing, the resulting coating can remove formaldehyde and purify the air environment in the space. The amount of UV formaldehyde-removing resin added to the UV coating accounts for 1%-35% of the total mass of the coating formulation, such as 10%-30%.

[0164] This invention also discloses a formaldehyde-removing coating, which includes the aforementioned UV formaldehyde-removing resin. The formaldehyde-removing coating may include one of the aforementioned UV formaldehyde-removing resins, or a combination of at least two different aforementioned UV formaldehyde-removing resins.

[0165] The present invention further discloses a method for preparing the above-mentioned formaldehyde removal coating: the UV formaldehyde removal resin can be formulated into a UV coating. After coating, the UV formaldehyde removal resin can quickly migrate and accumulate on the coating surface, thereby improving the utilization rate of the formaldehyde removal resin. After UV curing, it can effectively remove formaldehyde and improve the formaldehyde removal efficiency.

[0166] In this invention, the reaction of an active methylene group or a cycloethylene urea containing a secondary amino group with formaldehyde is as follows:

[0167]

[0168]

[0169] The formaldehyde removal efficiency test method in this invention refers to the method of JCT 10742008 "Purification performance of functional coating materials for indoor air purification". The test examines the change in formaldehyde concentration after 24 hours in a closed chamber environment with a temperature of (20±2)℃ and a relative humidity of (50±10)% to calculate the formaldehyde removal efficiency or formaldehyde purification efficiency.

[0170] Example 1

[0171] Add 100g of hydroxymonoamine siloxane (amine value 0.6 mmol / g), 6.96g of methyl acetoacetate, and 0.2g of p-toluenesulfonic acid to a reaction vessel. Purge with nitrogen, heat slowly, and start stirring. Raise the temperature to 100℃ and react for 3-5 hours. The hydroxymonoamine siloxane and methyl acetoacetate undergo transesterification, and the byproduct methanol is removed. Collect and weigh the methanol to monitor the reaction progress. Raise the temperature to 130-150℃, adjusting the temperature to allow for a suitable rate of methanol removal. Take a sample to test the remaining methyl acetoacetate content in the reaction solution. When the content is less than 0.1% (mass fraction), cool the solution to 7℃. At 0℃, add 0.02g of p-methoxyphenol and dropwise add 8.52g of glycidyl methacrylate. React for 1-2 hours. When the 908cm-1 value disappears in the infrared spectrum of the reaction solution, add 13.32g of isophorone diisocyanate to the reactor. Raise the temperature to 90℃ and react for 1-2 hours. When the NCO content drops to 1.96%, add 5.16g of cycloethylene urea to the reactor. Raise the temperature to 110℃ and react for 2-3 hours. When the 2270cm-1 value disappears in the infrared spectrum of the reaction solution, stop the reaction and cool down to discharge the product.

[0172] Example 2

[0173] Add 100g of methyldiamine siloxane (amine value 0.9 mmol / g), 12.78g of glycidyl methacrylate, and 0.03g of 2,4,6-trinitrophenol to a reaction vessel, start stirring, raise the temperature to 70℃, and react for 1-2 hours. When the 908cm-1 value disappears in the infrared spectrum of the reaction solution, add 15.66g of toluene diisocyanate to the reaction vessel, raise the temperature to 80℃, and react for 2-3 hours. When the NCO content drops to 2.93%, add 7.74g of cyclovinyl urea to the reaction vessel, raise the temperature to 105℃, and react for 2-3 hours. When the 2270cm-1 value disappears in the infrared spectrum of the reaction solution, stop the reaction, cool down, and discharge the material.

[0174] Example 3

[0175] Add 100g of hydroxyvinylsiloxane (7% vinyl content, 6% hydroxyl content), 45.88g of ethyl acetoacetate, 0.2g of tetrabutyl titanate, and 0.15g of hydroquinone to a reaction vessel, purge with nitrogen, heat slowly, start stirring, and raise the temperature to 100℃. React for 3-5 hours. The hydroxyvinylsiloxane and ethyl acetoacetate undergo transesterification, and the byproduct ethanol is removed. Carefully collect and weigh the ethanol to determine the reaction progress. Raise the temperature to 130-160℃, adjusting the temperature to allow for a suitable rate of ethanol removal. Take a sample to test the remaining ethyl acetoacetate content in the reaction solution. When the content is less than 0.1% (mass fraction), stop the reaction, cool down, and discharge the product.

[0176] Example 4

[0177] Add 100g of hydroxyvinylsiloxane (6.5% vinyl content, 6% hydroxyl content), 78.35g of isophorone diisocyanate, and 0.13g of 2,6-di-tert-butyl-p-cresol to a reaction vessel, heat slowly, start stirring, raise the temperature to 90℃, and react for 2-3 hours. When the NCO content drops to 8.31%, add 30.35g of cyclovinylurea to the reaction vessel, raise the temperature to 110℃, and react for 2-3 hours. When the infrared spectrum of the reaction solution disappears at 2270cm-1, stop the reaction, cool down and discharge the material.

[0178] Comparative Example 1

[0179] Add 100g of hydroxyethyl methacrylate (excluding siloxane segments), 89g of methyl acetoacetate, 0.2g of p-toluenesulfonic acid, and 0.2g of p-methoxyphenol to a reaction vessel, purge with nitrogen, heat slowly, start stirring, and raise the temperature to 100℃. React for 3-5 hours. Hydroxyethyl methacrylate and methyl acetoacetate undergo transesterification, and the byproduct methanol is removed. Collect and weigh the methanol to determine the reaction progress. Raise the temperature to 130-150℃, adjusting the temperature to allow for a suitable rate of methanol removal. Take a sample to test the remaining methyl acetoacetate content in the reaction solution. When the content is less than 0.1% (mass fraction), cool down and discharge the product.

[0180] Comparative Example 2

[0181] Add 100g of hydroxypropyl methacrylate (excluding siloxane segments), 154.16g of isophorone diisocyanate, and 0.25g of 2,4,6-trinitrophenol to a reaction vessel, heat slowly, start stirring, and react for 2-3 hours when the temperature reaches 90℃. When the NCO content drops to 11.47%, add 59.72g of cyclovinyl urea, raise the temperature to 110℃, and react for 2-3 hours. Stop the reaction when the infrared spectrum of the reaction solution disappears at 2270cm-1, cool down and discharge the material.

[0182] Formaldehyde purification efficiency test

[0183] Based on the principle that the total molar amount of the characteristic structure of the formaldehyde removal substance (active methylene and cyclovinyl urea structure containing secondary amine group) is equal, each group of UV formaldehyde removal resins was added to the UV coating in proportion and cured. The formaldehyde purification efficiency of the cured coating was tested, and the test results are shown in Table 1.

[0184] Table 1 Formaldehyde Purification Efficiency Test Table for Coating

[0185]

[0186] Note: The formaldehyde removal efficiency test method refers to the JCT 1074-2008 "Purification Performance of Indoor Air Purification Functional Coating Materials" method. The test examines the change in formaldehyde concentration after 24 hours in a closed chamber environment with a temperature of (20±2)℃ and a relative humidity of (50±10)%, in order to calculate the formaldehyde removal efficiency or formaldehyde purification efficiency.

[0187] In summary, the formaldehyde-removing coating, UV formaldehyde-removing resin, and their preparation raw materials and methods proposed in this invention can improve the formaldehyde removal efficiency of UV formaldehyde-removing resin.

[0188] The UV formaldehyde removal resin prepared by this invention can be used to formulate UV curing products, especially UV coating products. This UV formaldehyde removal resin is modified with methylsiloxane. By utilizing the low surface tension and easy migration and enrichment of methylsiloxane to the surface, the utilization rate of the formaldehyde removal monomer is improved, and the formaldehyde removal monomer can maximize its function of purifying formaldehyde.

[0189] Furthermore, the formaldehyde removal mechanism of the formaldehyde removal resin in this invention utilizes the active methylene group or the cycloethylene urea structure containing a secondary amine group that reacts irreversibly with formaldehyde. It does not require harsh conditions such as light exposure, the formaldehyde removal process is stable, and there is no problem of secondary formaldehyde release. The formaldehyde removal product is a small molecule that only generates water. The formaldehyde removal process is environmentally friendly and safe, achieving the purpose of purifying the air environment.

[0190] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0191] The description and application of the present invention herein are illustrative and not intended to limit the scope of the invention to the embodiments described above. Effects or advantages involved in the embodiments may not be apparent due to various factors, and the description of effects or advantages is not intended to limit the embodiments. Variations and modifications of the embodiments disclosed herein are possible, and various substitutions and equivalents of the components in the embodiments are well known to those skilled in the art. It should be apparent to those skilled in the art that the invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials, and parts without departing from the spirit or essential characteristics of the invention. Other variations and modifications can be made to the embodiments disclosed herein without departing from the scope and spirit of the invention.

Claims

1. A method for preparing a UV-cured formaldehyde-removing resin, characterized in that, The preparation method includes: A first raw material having a siloxane structure is mixed with a second raw material, wherein the second raw material includes an active methylene group with aldehyde removal function and / or a cycloethylene urea containing a secondary amine group; An active methylene group or a cyclovinyl urea containing a secondary amine group with aldehyde removal function is introduced into the molecular chain of an oligomer resin with photocuring function via transesterification or isocyanate functional group to obtain a UV aldehyde removal resin. The general formula of the UV formaldehyde removal resin contains a siloxane structure, as well as an active methylene structure with formaldehyde removal function or a cyclovinyl urea structure containing a secondary amine group. The first raw material includes hydroxyaminosiloxane of formula (1) and / or methylaminosiloxane of formula (2) and / or hydroxyvinylsiloxane of formula (3), and the obtained UV formaldehyde removal resin has the structure shown in general formula I and / or general formula II and / or general formula III and / or general formula IV. ； Equation (1) ； Equation (2) In equations (1) and (2), R is monoammonium-CH2CH2CH2NH2 or diammonium-CH2CH2CH2NHCH2CH2NH2 or triammonium-C3H6NHC2H4NHC2H4NH2, and m and n are independent integers from 1 to 25. ； Equation (3) In equation (3), m and n are independent integers from 1 to 25; General formula I is as follows: ； In general formula I, CR1=CH2 is or or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25; Formula II is as follows: ； In general formula II, CR1=CH2 is or or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25; Formula III is as follows: ； In general formula III, m and n are independent integers from 1 to 25; Formula IV is as follows: ； In general formula IV, m and n are independent integers from 1 to 25; -CR1=CH2 structural units are introduced into the siloxane molecular chain through monomers or oligomers with dual curing functions; The monomer or oligomer with dual curing function must contain carbon-carbon double bonds and have epoxy or isocyanate functional groups; the carbon-carbon double bond functional group for photocuring is introduced by reacting epoxy or isocyanate groups with amine groups; the monomer or oligomer with dual curing function includes at least one of ethyl isocyanate acrylate, isocyanoethyl methacrylate, allyl isocyanate, and glycidyl methacrylate. When reacting with dual-curing functional monomers or hydroxyvinylsiloxanes, a polymerization inhibitor is added to prevent polymerization failure during product preparation and subsequent storage. The polymerization inhibitor includes at least one of the following: p-methoxyphenol, 2,4,6-trinitrophenol, 1,4-benzoquinone, hydroquinone, and 2,6-di-tert-butyl-p-cresol. The amount of polymerization inhibitor added is 0.01-0.3% of the total mass of the dual-curing monomers or hydroxyvinylsiloxanes. The structures of monomers with active methylene groups that participate in hydroxyl-containing siloxane ester exchange are as follows: ； Wherein, R4 is one of -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, that is, the monomer structure with an active methylene group includes one or a combination of at least two of methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, and tert-butyl acetoacetate; In general formulas I, II, and IV, the ethylene urea structural unit containing a secondary amine group is bridged with the amine or hydroxyl group in the siloxane via a diisocyanate reaction, and the ethylene urea structure is as follows: ； The diisocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

2. The preparation method according to claim 1, characterized in that: The preparation method further includes: Add the hydroxyaminosiloxane of formula (1) or the hydroxyvinylsiloxane of formula (3), a monomer containing an active methylene group, and a catalyst to the reactor, and carry out transesterification under an inert gas. The reaction ends when the residual amount of the active methylene monomer is less than 0.1%, thereby introducing the active methylene structure into the siloxane chain segment. The catalyst is one or a mixture of several of p-toluenesulfonic acid, tetrabutyl titanate, and dibutyltin dilaurate, and the amount of catalyst added is 0.05-1% of the total mass of the active methylene monomer and the aminosiloxane or hydroxyvinylsiloxane; The specific transesterification process is as follows: Under inert gas protection, the materials fed in proportion are stirred and heated to 100-130℃, and reacted for 3-5 hours. The temperature is then increased to 130-180℃ to continue the reaction. The residual amount of active methylene monomer is tested, and the reaction is stopped when its content is less than 0.1%. Alternatively, the preparation method further includes: The process of introducing a cyclovinylurea structural unit containing a secondary amine group into an aminosiloxane or a hydroxyvinylsiloxane includes: for aminosiloxanes, the introduction is achieved by reacting a diisocyanate with the amine group or the hydroxyl group formed after the epoxy group in the aminosiloxane ring-opening to form an isocyanate end cap, followed by the addition of cyclovinylurea; for hydroxyvinylsiloxanes, the process involves reacting a diisocyanate with the terminal hydroxyl group to form an isocyanate end cap, followed by the addition of cyclovinylurea. The endpoint of the reaction between the epoxy group and the amine group is determined by the disappearance of the characteristic absorption peak in the infrared spectrum of the reaction solution. The reaction temperature of amino groups with diisocyanates is 40-60℃, the reaction temperature of hydroxyl groups with diisocyanates is 60-120℃, and the reaction temperature of cycloethylene urea with isocyanate functional groups is 100-120℃. The reaction endpoint is determined by the NCO content or the disappearance of characteristic absorption peaks in the infrared spectrum of the reaction solution.

3. A UV formaldehyde-removing resin prepared by any one of claims 1 to 2, characterized in that, In addition to carbon-carbon double bonds, the general formula of the UV formaldehyde removal resin also contains a siloxane structure, an active methylene structure with formaldehyde removal function, or a cyclovinyl urea structure containing a secondary amine group.

4. The UV formaldehyde-removing resin according to claim 3, characterized in that: The UV formaldehyde removal resin includes an active methylene structure with formaldehyde removal function or an oligomer of cyclovinyl urea containing a secondary amine group. The structure of the reactive methylene group with formaldehyde removal function is as follows: ； The structure of a cyclovinyl urea containing a secondary amine group is as follows: ； Among them, R2 and R3 are the remaining segments of the photocurable formaldehyde-removing resin; The siloxane structure is as follows: ； The UV formaldehyde removal resin includes a structure as shown in general formula I, general formula II, general formula III, or general formula IV. General formula I is as follows: ； In general formula I, CR1=CH2 is or or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25; Formula II is as follows: ； In general formula II, CR1=CH2 is or or p and q are independent integers from 1 to 4, and m and n are independent integers from 1 to 25; Formula III is as follows: ； In general formula III, m and n are independent integers from 1 to 25; Formula IV is as follows: ； In general formula IV, m and n are independent integers from 1 to 25.

5. The UV formaldehyde-removing resin according to claim 3 or 4, characterized in that: The UV formaldehyde removal resin includes a structure that can participate in the photocuring reaction, and the structure that can participate in the photocuring reaction includes one or more of vinyl, acrylate, and methacrylate structural units; By introducing active methylene groups or cyclovinyl urea containing secondary amine groups with aldehyde removal function into the molecular chain of oligomer resin with photocuring function through transesterification or isocyanate functional groups, a UV aldehyde removal resin is obtained.

6. A formaldehyde-removing coating, characterized in that: The formaldehyde-removing coating includes the UV formaldehyde-removing resin according to any one of claims 3 to 5.

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