Rotary screen printing adhesive, raw material composition thereof, preparation method and application thereof

Abstract

The present invention relates to a rotary screen printing adhesive, a raw material composition thereof, a preparation method thereof, and an application thereof. The adhesive comprises the following components in parts by weight: 330-350 parts of a soft monomer, 110-115 parts of a hard monomer, 11-25 parts of a cross-linking monomer, 5-6 parts of an anionic emulsifier, and 1-1.5 parts of a nonionic emulsifier, wherein: the soft monomer is an acrylate soft monomer having a glass transition temperature of 20-70°C; the hard monomer is composed of an acrylate hard monomer having a glass transition temperature of 90-110°C and styrene, with the weight ratio of the acrylate hard monomer to styrene being 1:1.5-5; and the cross-linking monomer is a reactive monomer containing an acryloyl or acrylamide functional group. The adhesive prepared by the present invention has a soft feel, improved friction resistance, does not clog the screen during rotary screen printing, and has good color development.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, in particular to a rotary screen printing adhesive, a raw material composition thereof, a preparation method thereof and applications thereof. Background Art

[0002] Pigment printing is suitable for most textiles, offering vibrant colors and eliminating the need for post-printing washes, shortening the process and saving water. Rotary screen printing, with its high production efficiency and adaptability to fabrics, is one of many printing methods. However, due to limitations in the rotary screen structure and the composition of some printing adhesives, pigment printing pastes are prone to screen clogging during the rotary screen printing process. Furthermore, due to the influence of the printing adhesive composition, some finished products also suffer from poor color development, making them difficult to meet the demands of continuous production.

[0003] Patent CN 113265888A discloses a high-fastness pigment printing adhesive and its preparation method. By selecting vinyl silicone oil and grafting silicone oil segments onto acrylate polymer segments, the water resistance of the adhesive is improved, thereby improving the dry / wet friction fastness of the printing. The use of ethylene glycol as a solvent further enhances the stability of the adhesive emulsion system and improves the surface tension of the adhesive emulsion, thereby increasing the stability of the formulated pigment printing paste and improving the permeability of the printing paste. However, this patented technical solution mainly improves product performance by adding vinyl silicone oil and ethylene glycol to the acrylate polymer formed after the polymerization reaction. The defect is that the additional introduction of vinyl silicone oil may cause the viscosity of the adhesive to increase, making the coating or construction process difficult. In addition, the introduction of vinyl silicone oil may also reduce the mechanical strength and shear resistance of the adhesive, causing the performance of the adhesive to decline in some high-load or high-stress environments. The additional introduction of ethylene glycol as a solvent will increase the volatility of the adhesive, leading to solvent volatilization problems during coating or construction, which will lead to increased toxicity of the adhesive (such as formaldehyde exceeding the standard), posing potential risks to human health and the environment, and posing environmental risks.

[0004] Therefore, how to provide an economical, environmentally friendly, and formula-optimized rotary screen printing adhesive remains a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems and provide a more economical and environmentally friendly rotary screen printing adhesive. Through formula optimization and process design, the problems of easy screen clogging and poor color development in the rotary screen printing process are solved.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A raw material composition for a rotary screen printing adhesive is composed of the following components in parts by weight:

[0008] 330-350 parts of soft monomer, 110-115 parts of hard monomer, 11-25 parts of crosslinking monomer, 5-6 parts of anionic emulsifier, 1-1.5 parts of nonionic emulsifier, including:

[0009] The soft monomer is an acrylic soft monomer with a glass transition temperature of -20 to -70°C;

[0010] The hard monomer is composed of an acrylic acid ester hard monomer having a glass transition temperature of 90 to 110° C. and styrene, and the weight ratio of the acrylic acid ester hard monomer to styrene is 1:1.5 to 5;

[0011] The cross-linking monomer is a reactive monomer containing an acryl group or an acrylamide functional group.

[0012] As a preferred technical solution of the present invention, in the raw material composition, the soft monomer is selected from one or more of methyl acrylate, ethyl acrylate, butyl acrylate, and isooctyl acrylate. Preferably, the soft monomer consists of n-butyl acrylate, isooctyl acrylate, and ethyl acrylate, and the mass ratio of n-butyl acrylate, isooctyl acrylate, and ethyl acrylate is 260-300:30-40:20-30.

[0013] As a preferred technical solution of the present invention, in the raw material composition, the acrylic ester hard monomer is selected from one or more of methyl methacrylate and butyl methacrylate, preferably, methyl methacrylate.

[0014] As a preferred technical solution of the present invention, in the raw material composition, the cross-linking monomer is selected from one or more of hydroxyethyl acrylate, acrylic acid, diacetone acrylamide, glycidyl acrylate, and N-hydroxymethyl acrylamide. Preferably, the cross-linking monomer consists of acrylic acid and N-hydroxymethyl acrylamide, and the mass ratio of acrylic acid to N-hydroxymethyl acrylamide is 10-20:1-5.

[0015] As a preferred technical solution of the present invention, in the raw material composition, the anionic emulsifier is selected from one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium dodecylsulfonate. Preferably, the anionic emulsifier is sodium dodecyl sulfate with an HLB value of 35-45, and more preferably, sodium dodecyl sulfate with an HLB value of about 40 is selected.

[0016] As a preferred technical solution of the present invention, in the raw material composition, the nonionic emulsifier is selected from fatty alcohol polyoxyethylene ethers with an HLB value of 13-14 and a cloud point of 70-95.

[0017] A rotary screen printing adhesive is obtained by emulsion polymerization of the raw material composition described above with water as solvent under the action of an initiator.

[0018] A method for preparing a rotary screen printing adhesive comprises the following steps:

[0019] (1) Prepare raw materials according to the formula components;

[0020] (2) adding 35-40% of the total weight of water into an emulsifier, adding 80-90% of the total weight of anionic emulsifier, all nonionic emulsifiers, and all monomer raw materials, stirring and pre-emulsifying to obtain a pre-emulsified liquid;

[0021] (3) Add 45% to 55% of the total mass of water to the reactor, and the remaining anionic emulsifier, start stirring, raise the temperature to 84-86°C, and use the remaining water to dissolve the initiator for later use;

[0022] (4) Add 25-50% of the total mass of the initiator to the reactor, add 3-5% of the pre-emulsion after 2-3 minutes, and initiate the reaction for 8-12 minutes;

[0023] (5) After the pre-reaction is completed, the temperature of the reactor is stabilized at 84-86°C, and the remaining pre-emulsion and initiator are added dropwise to the reactor for 3.5-4 hours. After the addition is completed, the reaction is kept warm for 0.5-2 hours;

[0024] (6) After the insulation is completed, the temperature is lowered to 72-75°C, and the redox initiator is added dropwise, and the reaction is continued for 0.5-2 hours;

[0025] (7) After the reaction is completed, the temperature is lowered to below 45° C., a defoamer and a preservative are added dropwise, and ammonia water is added dropwise to adjust the pH to 6-8 to obtain the rotary screen printing adhesive.

[0026] As a preferred technical solution of the present invention, the rotary screen printing adhesive is prepared according to the following formula: 800 parts of water, 260-300 parts of n-butyl acrylate, 20-30 parts of ethyl acrylate, 20-40 parts of methyl methacrylate, 20-40 parts of isooctyl acrylate, 70-90 parts of styrene, 10-20 parts of acrylic acid, 1-5 parts of N-hydroxymethyl acrylamide, 5-6 parts of anionic emulsifier, 1-1.5 parts of nonionic emulsifier, 1-2 parts of initiator, 1-1.5 parts of redox initiator, 1-1.5 parts of defoaming agent, 1-1.5 parts of preservative, and 5-15 parts of ammonia water.

[0027] Further preferably, the rotary screen printing adhesive has the following raw materials: 800 parts of water, 260-300 parts of n-butyl acrylate, 20-30 parts of ethyl acrylate, 20-40 parts of methyl methacrylate, 30-40 parts of isooctyl acrylate, 70-90 parts of styrene, 10-20 parts of acrylic acid, 1-5 parts of N-hydroxymethyl acrylamide, 5-6 parts of anionic emulsifier, 1-1.5 parts of nonionic emulsifier, 1.5-2 parts of initiator, 1-1.5 parts of redox initiator, 1-1.5 parts of defoaming agent, 1-1.5 parts of preservative, and 10-15 parts of ammonia water. For example, in a specific embodiment, the rotary screen printing adhesive can be prepared according to the following formula: 800 parts of water, 280 parts of n-butyl acrylate, 25 parts of ethyl acrylate, 32 parts of methyl methacrylate, 35 parts of isooctyl acrylate, 80 parts of styrene, 15 parts of acrylic acid, 3 parts of N-hydroxymethyl acrylamide, 5.7 parts of anionic emulsifier, 1.2 parts of nonionic emulsifier, 2 parts of initiator, 1 part of redox initiator, 1 part of defoamer, 1 part of preservative, and 12 parts of ammonia water.

[0028] As a preferred technical solution of the present invention, the initiator includes sodium persulfate, potassium persulfate, and ammonium persulfate. More preferably, the initiator is ammonium persulfate.

[0029] As a preferred technical solution of the present invention, the redox initiator includes tert-butyl hydroperoxide-diaobai powder, tert-butyl hydroperoxide-vitamin C, hydrogen peroxide-diaobai powder, and hydrogen peroxide-vitamin C.

[0030] For example, tert-butyl hydroperoxide can be selected from Taizhou Haixiang Chemical Co., Ltd., and disulfide can be selected from Tianjin Zhentai Chemical Co., Ltd.; hydrogen peroxide can be selected from Shanghai Jinshi Chemical Co., Ltd., and vitamin C can be selected from Zhejiang Yunmo Biotechnology Co., Ltd.

[0031] As a preferred technical solution of the present invention, the defoaming agent and preservative are commercially available conventional components, such as Nopco NXZ, Rohm and Haas LXE, etc.

[0032] The adhesive is used in pigment printing as its adhesive component.

[0033] After research, the inventors discovered that the possible reason for the screen clogging of pigment printing adhesives during rotary screen printing is poor adhesive stability, an incompatible type of emulsifier used in the adhesive emulsion polymerization process, or an insufficient proportion of emulsifier, resulting in poor emulsion stability. During the rotary screen printing process, under the action of external force, the emulsion breaks and slags out, causing screen clogging. The color development problem is caused by the weak wettability of the adhesive. When the adhesive has poor wettability, the adhesive has poor compatibility with organic pigments and poor compatibility with color paste, resulting in reduced color paste stability and poor adhesion to the printing substrate, affecting the uniformity and color development of the color paste.

[0034] Based on this research, the inventors have provided a rotary screen printing adhesive product solution with excellent effects through formula and process improvements. The present invention uses an acrylic ester soft monomer with a glass transition temperature of -20 to -70°C as a main monomer component. After the acrylic soft monomer polymer is formed into a film, it gives the product good elasticity, softness and ductility, so that the product maintains a soft and plump feel. A hard monomer composed of an acrylic ester hard monomer with a glass transition temperature of 90 to 110°C and styrene is introduced. A small part of the acrylic hard monomer adjusts the feel and toughness of the adhesive after film formation, and most of the styrene monomer has excellent tensile strength and abrasion resistance after film formation, giving the product good dry and wet fastness. Styrene helps to adjust the viscosity and fluidity of the adhesive, making the adhesive easier to apply. At the same time, it has high durability, improves the water resistance, solvent resistance and high temperature resistance of the adhesive, and greatly improves the stability of the adhesive. In addition, the cross-linking monomer provides a reactive group acryloyl or acrylamide functional group, so that during the film formation process of the adhesive, the reactive group is cross-linked between the adhesive macromolecular chains to form a network structure, and can also directly react with the fiber substrate to improve the solvent resistance and heat resistance of the printed product and improve the friction fastness.

[0035] In addition, another key point of the present invention lies in the selection of emulsifiers. The present invention selects a suitable anionic emulsifier and a suitable nonionic emulsifier, especially the introduction of a fatty alcohol polyoxyethylene ether reactive nonionic emulsifier with an HLB value of 13-14 and a cloud point of 70-95. This allows the emulsion to be more fully cross-linked, imparts emulsion stability, avoids demulsification during the scraping and extrusion process of the printing paste, and reduces the phenomenon of printing paste clogging. At the same time, the nonionic emulsifier improves the wettability of the adhesive emulsion, increases the compatibility of the adhesive emulsion with the organic pigment paste, improves the color development of the printing paste, increases the compatibility of the emulsion with the organic pigment, and reduces the dispersed pigment particles in the printing paste.

[0036] Compared with the existing technology, such as patent CN 113265888A, the present invention does not require the subsequent addition of vinyl silicone oil and ethylene glycol to improve product performance. Only by reasonably adjusting the formula, a rotary screen printing adhesive with good fastness, color development and environmental protection can be prepared.

[0037] The printing adhesive produced by the present invention has a glass transition temperature of -5°C to -10°C. The adhesive emulsion has a soft feel after film formation, and the emulsion particle size is 100 to 150 nm. This small particle size facilitates a denser film surface and helps improve friction resistance. The printing adhesive of the present invention has high stability, strong wettability, good compatibility with organic pigments, easy thickening, and is not prone to screen clogging during application. The finished product has excellent color development, a soft feel after film formation, and good solvent resistance, heat resistance, and abrasion fastness. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below with reference to specific embodiments, but the present invention is by no means limited thereto.

[0039] Table 1 is the specific formula of Examples and Comparative Examples.

[0040] The preparation method of rotary screen printing adhesive comprises the following steps:

[0041] (1) Prepare raw materials according to the formula components;

[0042] (2) adding 35-40% of the total weight of water into an emulsifier, adding 80-90% of the total weight of anionic emulsifier, all nonionic emulsifiers, and all monomer raw materials, stirring and pre-emulsifying to obtain a pre-emulsified liquid;

[0043] (3) Add 45% to 55% of the total mass of water to the reactor, and the remaining anionic emulsifier, start stirring, raise the temperature to 84-86°C, and use the remaining water to dissolve the initiator for later use;

[0044] (4) Add 25-50% of the total mass of the initiator to the reactor, add 3-5% of the pre-emulsion after 2-3 minutes, and initiate the reaction for 8-12 minutes;

[0045] (5) After the pre-reaction is completed, the temperature of the reactor is stabilized at 84-86°C, and the remaining pre-emulsion and initiator are added dropwise to the reactor for 3.5-4 hours. After the addition is completed, the reaction is kept warm for 0.5-2 hours;

[0046] (6) After the insulation is completed, the temperature is lowered to 72-75°C, and the redox initiator is added dropwise, and the reaction is continued for 0.5-2 hours;

[0047] (7) After the reaction is completed, the temperature is lowered to below 45° C., a defoamer and a preservative are added dropwise, and ammonia water is added dropwise to adjust the pH to 6-8 to obtain the rotary screen printing adhesive.

[0048] Table 1 Example and Comparative Example Composition Ratio (Unit: g)

[0049]

[0050] Among them, the specific sources of raw materials are:

[0051] Water: Deionized water produced by Shanghai Baolijia New Materials Co., Ltd.

[0052] Anionic emulsifier: sodium lauryl sulfate, China National Light Industry Group;

[0053] Nonionic emulsion: fatty alcohol polyoxyethylene ether, Hai'an Petrochemical Plant, Jiangsu Province;

[0054] Initiator: ammonium persulfate, Shanghai Tianyue Chemical Co., Ltd.

[0055] Redox initiator: tert-butyl hydroperoxide was selected from Taizhou Haixiang Chemical Co., Ltd., and dichloromethane was selected from Tianjin Zhentai Chemical Co., Ltd.

[0056] N-Hydroxymethyl acrylamide: Shandong Guanchang Chemical Technology Co., Ltd.;

[0057] Defoaming agent: Nopco NXZ;

[0058] Preservative: Rohm and Haas LXE

[0059] Other materials not specified are conventional commercially available raw materials in this field.

[0060] Example 1

[0061] A rotary screen printing adhesive. The raw materials for its preparation, calculated by weight, include: 800 parts of water, 280 parts of n-butyl acrylate, 25 parts of ethyl acrylate, 32 parts of methyl methacrylate, 35 parts of isooctyl acrylate, 80 parts of styrene, 15 parts of acrylic acid, 3 parts of N-hydroxymethyl acrylamide, 5.7 parts of anionic emulsifier, 1.2 parts of nonionic emulsifier, 2 parts of initiator, 1 part of redox initiator, 1 part of defoaming agent, 1 part of preservative, and 12 parts of aqueous ammonia.

[0062] The preparation method specifically comprises the following steps:

[0063] (1) Prepare the raw materials according to the above formula components;

[0064] (2) First, add about 300 parts of water into the emulsification tank, add 5.2 parts of anionic emulsifier, 1.2 parts of nonionic emulsifier, 280 parts of n-butyl acrylate, 25 parts of ethyl acrylate, 32 parts of methyl methacrylate, 35 parts of isooctyl acrylate, 80 parts of styrene, 15 parts of acrylic acid, and 3 parts of N-hydroxymethyl acrylamide, and stir rapidly to pre-emulsify for 30 minutes.

[0065] (3) Add about 400 parts of water and 0.5 parts of anionic emulsifier to the reactor, start stirring, and raise the temperature to 84-86°C. Use the remaining water to dissolve the initiator for later use.

[0066] (4) Add 0.5 parts of initiator to the reactor, add 4% of emulsified monomer after 2 to 3 minutes, and initiate the reaction for 10 minutes.

[0067] (5) After the preliminary reaction, the temperature of the reactor was stabilized at 84-86°C, and the remaining emulsified monomer and initiator were added dropwise to the reactor for 3.5-4 hours. After the addition was complete, the reaction was kept warm for 1 hour.

[0068] (6) After the insulation is completed, the temperature is lowered to 72-75°C, and the redox initiator is added dropwise, and the reaction is continued for 1 hour.

[0069] (7) After the reaction is completed, the temperature is lowered to 45° C., and a defoamer, a preservative, and aqueous ammonia are added dropwise to adjust the pH to about 7. The rotary screen printing adhesive is obtained.

[0070] Example 2

[0071] A rotary screen printing adhesive. The raw materials for its preparation, calculated by weight, include: 800 parts of water, 260 parts of n-butyl acrylate, 30 parts of ethyl acrylate, 20 parts of methyl methacrylate, 40 parts of isooctyl acrylate, 90 parts of styrene, 20 parts of acrylic acid, 1 part of N-hydroxymethyl acrylamide, 6 parts of anionic emulsifier, 1 part of nonionic emulsifier, 1.8 parts of initiator, 1.2 parts of redox initiator, 1.2 parts of defoaming agent, 1.2 parts of preservative, and 13 parts of aqueous ammonia.

[0072] In this embodiment, the rotary screen printing adhesive was prepared in the same manner.

[0073] Example 3

[0074] A rotary screen printing adhesive and a preparation method thereof. The raw materials for the preparation thereof, calculated by weight, include: 800 parts of water, 300 parts of n-butyl acrylate, 20 parts of ethyl acrylate, 40 parts of methyl methacrylate, 30 parts of isooctyl acrylate, 70 parts of styrene, 10 parts of acrylic acid, 5 parts of N-hydroxymethyl acrylamide, 5 parts of anionic emulsifier, 1.5 parts of nonionic emulsifier, 1.5 parts of initiator, 1.5 parts of redox initiator, 1.5 parts of defoaming agent, 1.5 parts of preservative, and 15 parts of aqueous ammonia.

[0075] In this embodiment, the rotary screen printing adhesive was prepared in the same manner.

[0076] Comparative Example 1

[0077] Compared with Example 1, the emulsifier is different. In Comparative Example 1, no nonionic emulsifier is used, and the amount of anionic emulsifier is increased.

[0078] A rotary screen printing adhesive. The raw materials for its preparation, calculated by weight, include: 800 parts of water, 280 parts of n-butyl acrylate, 25 parts of ethyl acrylate, 32 parts of methyl methacrylate, 35 parts of isooctyl acrylate, 80 parts of styrene, 15 parts of acrylic acid, 3 parts of N-hydroxymethyl acrylamide, 6 parts of anionic emulsifier, 2 parts of initiator, 1 part of redox initiator, 1 part of defoaming agent, 1 part of preservative, and 12 parts of aqueous ammonia.

[0079] In this comparative example, the rotary screen printing adhesive was prepared in the same manner.

[0080] Comparative Example 2

[0081] Compared with Example 2, N-hydroxymethyl acrylamide is not used, acrylic acid is increased, and other aspects are the same as Example 2.

[0082] A rotary screen printing adhesive. The raw materials for its preparation, calculated by weight, include: 800 parts of water, 260 parts of n-butyl acrylate, 30 parts of ethyl acrylate, 20 parts of methyl methacrylate, 40 parts of isooctyl acrylate, 90 parts of styrene, 20 parts of acrylic acid, 6 parts of anionic emulsifier, 1 part of nonionic emulsifier, 1.8 parts of initiator, 1.2 parts of redox initiator, 1.2 parts of defoaming agent, 1.2 parts of preservative, and 13 parts of aqueous ammonia.

[0083] In this comparative example, the rotary screen printing adhesive was prepared in the same manner.

[0084] Comparative Example 3

[0085] Compared with Example 3, the main difference is that N-hydroxymethyl acrylamide and nonionic emulsifier are not used, and the amount of acrylic acid and anionic emulsifier is increased.

[0086] A rotary screen printing adhesive. The raw materials for its preparation, calculated by weight, include: 800 parts of water, 300 parts of n-butyl acrylate, 20 parts of ethyl acrylate, 40 parts of methyl methacrylate, 30 parts of isooctyl acrylate, 70 parts of styrene, 20 parts of acrylic acid, 5.7 parts of anionic emulsifier, 2 parts of initiator, 1 part of redox initiator, 1.5 parts of defoaming agent, 1.5 parts of preservative, and 15 parts of aqueous ammonia.

[0087] In this comparative example, the rotary screen printing adhesive was prepared in the same manner.

[0088] Comparative Example 4

[0089] Compared with Example 1, styrene is not used in the hard monomer, and only methyl methacrylate is used. The rest is the same as Example 1.

[0090] Comparative Example 5

[0091] An adhesive prepared using the technical solution described in Example 1 disclosed in patent CN113265888A was used as a comparison.

[0092] That is, 26 g of butyl acrylate, 5 g of isooctyl acrylate, 9 g of methyl methacrylate, 0.5 g of acrylic acid, 0.8 g of N-hydroxymethyl acrylamide, 0.5 g of sodium lauryl sulfate, 0.5 g of fatty alcohol polyoxyethylene ether AEO-9, 0.1 g of ammonium persulfate, and 21 g of deionized water were weighed and added into an emulsification tank, and stirred at 20-25 Hz for 30 minutes to obtain a pre-emulsion.

[0093] 33g of deionized water was added to the reactor, and 3.17g of pre-emulsion was added to the reactor at the same time. The reactor began to heat up and the temperature was controlled to 75℃~80℃. When the temperature rose to 78℃, the remaining pre-emulsion was added dropwise and the solution was added within 1 hour. During the addition process, the reactor temperature was controlled at 75℃~85℃.

[0094] After the dropwise addition was completed, 0.2 g of vinyl silicone oil and 2 g of ethylene glycol were added to the reactor, and the temperature was controlled to 85° C. to 90° C. for 30 minutes.

[0095] Cool down to 65℃~70℃ and add 1g of ammonia water.

[0096] Stop stirring, filter and collect the material to obtain the pigment printing adhesive.

[0097] Comparative Example 6

[0098] According to the scheme described in Comparative Example 5, the step of adding vinyl silicone oil and ethylene glycol is removed to obtain a pigment printing adhesive.

[0099] Comparative Example 7

[0100] The commercially available FS-460 from Liaoning Hengxing Fine Chemical Co., Ltd. was used as a reference.

[0101] Comparative Example 8

[0102] The commercially available FS-350 produced by Liaoning Hengxing Fine Chemical Co., Ltd. was used as a reference.

[0103] Examples 1 to 3 and Comparative Examples 1 to 8 were applied to fabric pigment printing, and washing fastness tests were carried out in accordance with GB / T Textiles - Tests for Color Fastness to Washing - Color Fastness to Soaping. The color difference between the samples and the standard was measured using a colorimeter to evaluate the color development. The particle size was tested using a Malvern particle size tester, and the clogging of the mesh was evaluated by observation. The specific results are shown in Table 2.

[0104] Table 2 Comparison of test results of different samples

[0105]

[0106] Note:

[0107] The smaller the particle size, the easier it is for the emulsion to obtain a dense film surface, which helps to improve the friction resistance;

[0108] The lower the formaldehyde content, the more environmentally friendly it is. The standard requirement is ≤500ppm;

[0109] The lower the slag discharge rate, the more stable the emulsion;

[0110] The higher the washing fastness grade, the better the fastness;

[0111] The smaller the color difference with the standard sample, the smaller the color difference and the better the color development.

[0112] As shown in Table 1, the coatings in Examples 1 and 3 exhibit the best wash fastness, with minimal color difference from the standard sample. In terms of the synthetic formula, Examples 1 and 3 contain a relatively high proportion of the crosslinking monomers acrylic acid and N-methylol acrylamide, which together impart excellent fastness to the emulsions. Furthermore, the relatively high proportion of nonionic emulsifiers in Examples 1 and 3 contributes to the excellent wettability of the emulsions, resulting in excellent color development in the coatings.

[0113] Comparative Example 1 does not contain a nonionic emulsifier but contains a cross-linking monomer N-methylol acrylamide, so its fastness is good but the color difference is large; Comparative Examples 2 and 3 do not contain a cross-linking monomer N-methylol acrylamide, so the fastness of the latter two is worse than that of the former.

[0114] Comparative Example 2 contains a nonionic emulsifier but no crosslinking monomer N-methylolacrylamide, while Comparative Example 3 contains neither the crosslinking monomer N-methylolacrylamide nor the nonionic emulsifier. The color difference between the two is similar, indicating that in addition to the wettability of the emulsion, the fastness of the emulsion also affects the color development. In other words, an emulsion with good fastness is more conducive to the color development of the printing paste. Otherwise, the printing paste is not easy to adhere to the fabric, and its color development is correspondingly deteriorated.

[0115] Comparative Example 4 does not contain styrene monomer, and its product has poor color fastness, because copolymerization of styrene and acrylic ester monomers is conducive to improving fastness.

[0116] Comparative Example 5 is Example 1 disclosed in CN113265888A. It can be seen that the color development of its product is slightly poor because organic solvents such as ethylene glycol will affect the pigment; and when vinyl silicone oil and ethylene glycol are not added in Comparative Example 6, the printing process is more prone to mesh clogging and sticking, and the product fastness is significantly reduced.

[0117] Comparative Examples 7 and 8 are similar products currently available on the market. Compared with them, the adhesive of the present invention is more environmentally friendly and has better fastness and color development.

[0118] In summary, the rotary screen printing adhesive provided by the present invention can obtain a printed coating with a soft feel, good fastness and color development, and the adhesive emulsion has a low formaldehyde content and is environmentally friendly. Compared with the existing technology, it has significant technological progress and has made a technical contribution.

[0119] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A rotary screen printing adhesive, characterized in that It is made of the following components in parts by weight: Soft monomer 330-350 parts, 110-115 parts of hard monomer, 11 to 25 parts of cross-linking monomer, 5-6 parts of anionic emulsifier, 1 to 1.5 parts of nonionic emulsifier, including: The soft monomer is an acrylic ester soft monomer with a glass transition temperature of -20 to -70°C, and the acrylic ester soft monomer is composed of n-butyl acrylate, isooctyl acrylate, and ethyl acrylate, and the mass ratio of n-butyl acrylate, isooctyl acrylate, and ethyl acrylate is 260 to 300:30 to 40:20 to 30; The hard monomer is composed of an acrylic acid ester hard monomer having a glass transition temperature of 90 to 110° C. and styrene, and the weight ratio of the acrylic acid ester hard monomer to styrene is 1:1.5 to 5; The acrylic hard monomer is methyl methacrylate; The cross-linking monomer is composed of acrylic acid and N-hydroxymethyl acrylamide, and the mass ratio of acrylic acid to N-hydroxymethyl acrylamide is 10-20:1-5; The anionic emulsifier is sodium lauryl sulfate with an HLB value of 35-45; The nonionic emulsifier is a fatty alcohol polyoxyethylene ether with an HLB value of 13-14 and a cloud point of 70-95.

2. A rotary screen printing adhesive according to claim 1, characterized in that: The composition is prepared by emulsion polymerization of the components as claimed in claim 1 with water as solvent and under the action of an initiator.

3. The method for preparing a rotary screen printing adhesive according to claim 2, wherein: The following steps are involved: (1) Prepare raw materials according to the formula components; (2) adding 35-40% of water by weight into an emulsifier, adding 80-90% of anionic emulsifier by weight, the nonionic emulsifier, the monomer raw materials including soft monomers, hard monomers and cross-linking monomers, stirring and pre-emulsifying to obtain a pre-emulsified liquid; (3) Add 45% to 55% of the total mass of water to the reactor, and the remaining anionic emulsifier, start stirring, raise the temperature to 84-86°C, and use the remaining water to dissolve the initiator for later use; (4) adding 25-50% of the total mass of the initiator to the reactor, and after 2-3 minutes, adding 3-5% of the total mass of the pre-emulsion to the reactor, and initiating the reaction for 8-12 minutes; (5) After the pre-reaction is completed, the temperature of the reactor is stabilized at 84-86°C, and the remaining pre-emulsion and initiator are added dropwise to the reactor for 3.5-4 hours. After the addition is completed, the reaction is kept warm for 0.5-2 hours; (6) After the insulation is completed, the temperature is lowered to 72-75°C, and the redox initiator is added dropwise, and the reaction is continued for 0.5-2 hours; (7) After the reaction is completed, the temperature is lowered to below 45° C., a defoamer and a preservative are added dropwise, and ammonia water is added dropwise to adjust the pH to 6-8 to obtain the rotary screen printing adhesive.

4. The method for preparing a rotary screen printing adhesive according to claim 3, wherein: The rotary screen printing adhesive is formulated with the following raw materials: 800 parts of water, 260-300 parts of n-butyl acrylate, 30-40 parts of isooctyl acrylate, 20-30 parts of ethyl acrylate, 20-40 parts of methyl methacrylate, 70-90 parts of styrene, 10-20 parts of acrylic acid, 1 to 5 parts of N-hydroxymethyl acrylamide, 5-6 parts of anionic emulsifier, 1 to 1.5 parts of nonionic emulsifier, 1 to 2 parts of initiator, 1 to 1.5 parts of redox initiator, 1 to 1.5 parts of defoaming agent, 1 to 1.5 parts of preservatives, 5-15 parts of ammonia water.

5. The method for preparing a rotary screen printing adhesive according to claim 4, wherein: The initiator is sodium persulfate, potassium persulfate, or ammonium persulfate; The redox initiator is tert-butyl hydroperoxide-sulfuric acid, tert-butyl hydroperoxide-vitamin C, hydrogen peroxide-sulfuric acid, and hydrogen peroxide-vitamin C.

6. The use of a rotary screen printing adhesive according to claim 1 or 2, characterized in that: The adhesive is used for pigment printing.

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