Photo transfer glue and preparation method thereof

Abstract

The invention discloses a photo transfer adhesive and a preparation method thereof, and relates to the technical field of glue, the photo transfer adhesive comprises the following raw materials by weight: 75%-85% of a water-based acrylic emulsion, 0.5%-1.0% of an alkali swelling thickener, 0.1%-0.3% of 2-amino-2-methyl-1-propanol, 5.0%-6.0% of deionized water, 3.0%-4.0% of glycerin, 5.0%-7.0% of dipropylene glycol dibenzoate, 2.5%-3.5% of propylene glycol, and 0.8%-1.0% of a preservative. During preparation, uniform mixing of the components is realized through step-by-step stirring and precise control of thickening and neutralizing time. The transfer glue solves the problems of poor environmental protection property, easy embrittlement of a glue film, unstable transfer effect and easy deterioration in storage of the existing product, has the advantages of environmental protection, no harmful substances, flexible and aging-resistant glue film, clear image transfer, high success rate and stable storage, and is suitable for DIY handwork, home decoration and other scenes.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, and more particularly to a photo transfer adhesive and its preparation method. Background Technology

[0002] Photo transfer adhesive is a type of special adhesive that can completely peel printed images from a carrier (such as paper) and firmly adhere them to various surfaces such as glass, wood, ceramics, and fabrics. It is widely used in DIY crafts, home décor, and personalized gift making. An ideal photo transfer adhesive needs to achieve a good balance between environmental friendliness, image transfer fidelity, film durability, and ease of use.

[0003] However, most products currently on the market have significant shortcomings in the aforementioned key performance aspects. Some products are still based on solvent-based systems, which not only have high volatile organic compound content and a strong pungent odor, but also pose fire safety hazards, making it difficult to meet modern environmental regulations and safe production requirements. More commonly, many water-based transfer adhesives have insufficient film flexibility design, making them prone to embrittlement and cracking after changes in environmental temperature and humidity or prolonged static storage, directly leading to damage or detachment of the transferred image. During the transfer process, due to the poor affinity and encapsulation of the adhesive with printing inks, problems such as blurred image edges and loss of highlight details often occur, making it difficult to exceed 85% in transfer success rate. In addition, the products generally lack water resistance and weather resistance, and images are prone to discoloration and warping in humid environments, seriously affecting the appearance and service life of the finished product.

[0004] To address these challenges, the industry has made some conventional improvements in materials and processes. For example, water-based acrylic emulsions are used instead of solvent-based resins to reduce VOC emissions; plasticizers or film-forming aids are added to improve film flexibility; or the basic adhesion is optimized by adjusting the formulation ratio. While these measures have promoted product environmental friendliness and improved basic performance to some extent, they have not fundamentally solved the problems.

[0005] Existing conventional technical solutions still have the following significant drawbacks: First, improvements in environmental friendliness are incomplete. Some solutions use phthalate plasticizers, which are restricted by regulations due to their potential ecotoxicity and have poor compatibility with water-based emulsions, easily migrating and precipitating from the film, leading to a significant decline in performance over time. Second, the system stability is insufficient. Commonly used ammonia neutralizers are volatile, causing significant fluctuations in pH and viscosity during storage (viscosity changes exceeding 20% ​​within 3 months for some products), affecting user experience and batch consistency. Third, the production process is relatively crude. If thickeners and other components are not mixed evenly during addition, local flocculation or clumping can easily occur, damaging the uniformity and smoothness of the final coating, thus affecting the clarity of image transfer. Finally, the operating window design is unreasonable, with generally short film open times (approximately 10-15 minutes), requiring high application skills from ordinary users; slight misjudgment can lead to transfer failure. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a photo transfer adhesive and its preparation method, which solves the problems of poor environmental performance, easy brittleness of the adhesive film, poor transfer effect, and unstable storage of existing products. By optimizing the formula and process, the product is made environmentally friendly, flexible and durable, with clear and stable transfer and easy storage.

[0007] Technical solution:

[0008] A photo transfer adhesive, comprising the following raw materials by weight percentage:

[0009] The composition includes 75%–85% acrylic emulsion, 0.5%–1.0% alkali-swelling thickener, 0.1%–0.3% 2-amino-2-methyl-1-propanol, 5.0%–6.0% deionized water, 3.0%–4.0% glycerol, 5.0%–7.0% dipropylene glycol dibenzoate, 2.5%–3.5% propylene glycol, and 0.8%–1.0% preservative, with the total weight percentage of all raw materials being 100%.

[0010] Dipropylene glycol dibenzoate is a high-boiling-point ester plasticizer with a large-volume benzene ring structure. Its molecular structure has good compatibility with polymer chains, effectively inserting into and separating polymer chains, weakening interchain forces, and thus playing a plasticizing role. Due to its large molecular weight and moderate polarity, it does not easily migrate and precipitate from the polymer network, and therefore can replace easily migrating small-molecule phthalates. 2-Amino-2-methyl-1-propanol is an organic amine with sufficient basicity to neutralize acidic groups in the system, but its boiling point is much higher than that of ammonia. The ammonium salt it forms in water is much less volatile than the ammonium salt formed by ammonia, thus providing a long-lasting and stable alkaline environment, avoiding system instability and viscosity changes caused by pH decrease.

[0011] Maintaining the dipropylene glycol dibenzoate content within the range of 5.0%–7.0% is crucial for achieving a balance between plasticizing efficiency and cohesive strength. At this ratio, it effectively lubricates acrylic emulsion particles and their molecular chains after film formation, enhancing chain mobility and resulting in a significant increase in elongation at break. Simultaneously, its solvation properties allow it to slightly swell the ink layer, enabling it to diffuse and entangle with ink components at the interface, forming a strong microscopic mechanical interlock. This greatly enhances ink affinity and ensures complete transfer of image details. Glycerin and propylene glycol are both small polyol molecules rich in hydroxyl groups, capable of forming strong hydrogen bonds with water molecules. During film drying, they preferentially bind to water, slowing down the evaporation rate. This "water-retention effect" delays the time it takes for emulsion particles to compactly aggregate and fuse into a dense film, thus providing users with a longer operating window (open time).

[0012] The stable alkaline environment (pH 8.0–9.0) provided by 2-amino-2-methyl-1-propanol is essential for the effectiveness of alkali-swellable thickeners. At this pH, the carboxyl groups on the thickener molecular chain are fully ionized. Due to electrostatic repulsion, the molecular chain extends from its coiled state and combines with water molecules, thus significantly increasing the system viscosity. A stable pH means that the extension state of the thickener molecular chain is constant, thereby maintaining the viscosity. Sufficient reaction time (60–120 minutes) ensures that the neutralization reaction and thickening process are complete and uniform, avoiding viscosity drift caused by slow reactions during subsequent storage.

[0013] When alkali-swellable thickeners encounter environments with high pH values ​​and high polymer concentrations, they can form non-redispersible gel particles due to excessively rapid local water absorption and swelling. Premixing, by highly diluting the thickener in deionized water, isolates the individual particles, allowing for initial swelling. Slow addition ensures that this initially swollen, relatively homogeneous mixture can be uniformly dispersed throughout the emulsion system under strong shear forces (stirring at 200–400 rpm), thus avoiding excessively high local concentrations and clumping, ultimately achieving high system homogeneity.

[0014] Furthermore, it is composed of the following raw materials by weight percentage:

[0015] Acrylic emulsion 78%–82%, alkali-swelling thickener 0.6%–0.9%, 2-amino-2-methyl-1-propanol 0.15%–0.25%, deionized water 5.3%–5.8%, glycerin 3.2%–3.8%, dipropylene glycol dibenzoate 5.5%–6.5%, propylene glycol 2.7%–3.3%, preservative 0.85%–0.95%.

[0016] Furthermore, it is composed of the following raw materials by weight percentage:

[0017] Acrylic emulsion 80.00%, alkali-swelling thickener 0.75%, 2-amino-2-methyl-1-propanol 0.20%, deionized water 5.60%, glycerin 3.50%, dipropylene glycol dibenzoate 6.00%, propylene glycol 3.00%, preservative 0.95%.

[0018] Furthermore, the dipropylene glycol dibenzoate is a highly solubilized plasticizer.

[0019] Furthermore, the preservative is an isothiazolinone preservative.

[0020] The present invention also discloses a method for the above-mentioned photo transfer adhesive, comprising the following steps:

[0021] S1: Add the prescribed amount of acrylic emulsion to the reactor and start stirring; S2: While stirring, slowly and evenly add the mixture consisting of the prescribed amount of alkali-swellable thickener and deionized water; S3: After the addition is complete, continue stirring for 20-40 minutes; S4: Slowly add the prescribed amount of 2-amino-2-methyl-1-propanol, and continue stirring for 60-120 minutes after the addition is complete; S5: Add the prescribed amounts of glycerol, dipropylene glycol dibenzoate, propylene glycol and preservative in sequence, and stir to mix evenly.

[0022] Furthermore, in step S2, the mixture is added over a period of 10 to 15 minutes.

[0023] Furthermore, the stirring speed in steps S1, S2, S4 and S5 is 200 to 400 rpm.

[0024] Furthermore, in step S5, the order of adding each material is as follows: first add glycerin, then add dipropylene glycol dibenzoate, then add propylene glycol, and finally add the preservative. After each material is added, it is necessary to stir for 5 to 10 minutes until it is evenly mixed before adding the next material.

[0025] Beneficial effects:

[0026] 1. By using the environmentally friendly plasticizer dipropylene glycol dibenzoate and the stabilizer and neutralizer 2-amino-2-methyl-1-propanol, the risk of phthalate esters and ammonia volatilization is completely eliminated.

[0027] 2. By controlling the content of dipropylene glycol dibenzoate at 5.0%–7.0%, it synergistically forms a stable system with acrylic emulsion, resulting in an elongation at break of over 300% for the film and significantly enhancing ink affinity, achieving image detail integrity exceeding 99%. The composite moisturizing system composed of glycerin and propylene glycol extends the film's open time to over 25 minutes, increasing the transfer success rate for ordinary users to 98%.

[0028] 3. By using 2-amino-2-methyl-1-propanol to stabilize the pH of the system at 8.0–9.0, combined with sufficient process reaction time, the viscosity instability caused by pH fluctuations is fundamentally overcome. After 6 months of storage, the viscosity change rate is less than 5%, the shelf life is significantly extended, and the batch performance difference is less than 3%.

[0029] 4. The process of slowly adding the alkali-swelling thickener after premixing it with deionized water effectively avoids local flocculation and agglomeration, improving the system uniformity by more than 40%. Detailed Implementation

[0030] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments. Experimental methods not specified in the embodiments are all operated according to conventional methods, and the raw materials used are all commercially available industrial-grade products.

[0031] Example 1

[0032] The formulation was designed with the goals of optimal environmental friendliness, transfer efficiency, and stability. The weight percentages of each raw material are as follows: water-based acrylic emulsion (solid content ≥45%) 80.00%, alkali-swellable thickener 0.75%, 2-amino-2-methyl-1-propanol 0.20%, deionized water 5.60%, glycerin 3.50%, dipropylene glycol dibenzoate 6.00%, propylene glycol 3.00%, and isothiazolinone preservatives 0.95%.

[0033] Preparation process: Add the formulated amount of aqueous acrylic emulsion to the reactor, start stirring, and adjust the speed to 250 rpm; while stirring, slowly add the mixture of alkali-swelling thickener and deionized water, and maintain stirring at 250 rpm for 30 minutes after the addition is complete (stirring stage after thickening and mixing); then slowly add 2-amino-2-methyl-1-propanol, and continue stirring at 250 rpm for 90 minutes after the addition is complete (neutralization reaction stage); finally, add glycerol, dipropylene glycol dibenzoate, propylene glycol, and isothiazolinone preservatives in sequence, maintaining stirring at 250 rpm for 10 minutes after each addition to ensure uniform mixing.

[0034] Example 2

[0035] To verify the effect of dipropylene glycol dibenzoate dosage on performance, the weight percentage of this component was adjusted to 5.00%. The weight percentages of the remaining raw materials were as follows: aqueous acrylic emulsion (solid content ≥45%) 80.00%, alkali-swellable thickener 0.75%, 2-amino-2-methyl-1-propanol 0.20%, deionized water 5.60%, glycerin 3.50%, propylene glycol 3.00%, and isothiazolinone preservatives 0.95%.

[0036] Preparation process: Add the formulated amount of aqueous acrylic emulsion to the reactor, start stirring and adjust to 250 rpm; slowly add the mixture of alkali swelling thickener and deionized water, and stir at 250 rpm for 30 minutes after the addition is complete; add 2-amino-2-methyl-1-propanol, and continue stirring at 250 rpm for 90 minutes; add glycerol, dipropylene glycol dibenzoate, propylene glycol, and isothiazolinone preservatives in sequence, and stir at 250 rpm for 10 minutes after each addition until homogeneous.

[0037] Example 3

[0038] To investigate the effect of the amount of 2-amino-2-methyl-1-propanol, its weight percentage was adjusted to 0.15%, and the weight percentage of deionized water was simultaneously slightly adjusted to 5.65% to ensure a total proportion of 100%. The weight percentages of the remaining raw materials were as follows: waterborne acrylic emulsion (solid content ≥45%) 80.00%, alkali-swellable thickener 0.75%, dipropylene glycol dibenzoate 6.00%, glycerin 3.50%, propylene glycol 3.00%, and isothiazolinone preservatives 0.95%.

[0039] Preparation process: Add the formulated amount of aqueous acrylic emulsion to the reactor, start stirring and adjust to 250 rpm; slowly add the mixture of alkali swelling thickener and deionized water, and stir at 250 rpm for 30 minutes after the addition is complete; add 2-amino-2-methyl-1-propanol, and continue stirring at 250 rpm for 90 minutes; add glycerol, dipropylene glycol dibenzoate, propylene glycol, and isothiazolinone preservatives in sequence, and stir at 250 rpm for 10 minutes after each addition until homogeneous.

[0040] Example 4

[0041] Focusing on the impact of the preparation process on the uniformity of the system, the weight percentage of raw materials is the same as in Example 1, namely: 80.00% aqueous acrylic emulsion (solid content ≥45%), 0.75% alkali-swelling thickener, 0.20% 2-amino-2-methyl-1-propanol, 5.60% deionized water, 3.50% glycerol, 6.00% dipropylene glycol dibenzoate, 3.00% propylene glycol, and 0.95% isothiazolinone preservative.

[0042] Preparation process: Add the formulated amount of aqueous acrylic emulsion to the reactor, start stirring and adjust to 250 rpm; slowly add the mixture of alkali-swelling thickener and deionized water, and stir at 250 rpm for 35 minutes after the addition is complete (extend the stirring time after thickening and mixing); add 2-amino-2-methyl-1-propanol, and continue stirring at 250 rpm for 95 minutes (extend the neutralization reaction time); add glycerol, dipropylene glycol dibenzoate, propylene glycol, and isothiazolinone preservatives in sequence, and stir at 250 rpm for 10 minutes after each addition until homogeneous.

[0043] Comparative Example 1

[0044] The conventional scheme for phthalic plasticizers in existing technologies is simulated, with the following raw material weight percentages: 80.00% aqueous acrylic emulsion (solid content ≥45%), 0.75% alkali-swellable thickener, 0.20% 2-amino-2-methyl-1-propanol, 5.60% deionized water, 3.50% glycerol, 6.00% dioctyl phthalate (DOP), 3.00% propylene glycol, and 0.95% isothiazolinone preservative.

[0045] Preparation process: Add the formulated amount of aqueous acrylic emulsion to the reactor, start stirring and adjust to 250 rpm; slowly add the mixture of alkali swelling thickener and deionized water, and stir at 250 rpm for 30 minutes after the addition is complete; add 2-amino-2-methyl-1-propanol, and continue stirring at 250 rpm for 90 minutes; add glycerol, dioctyl phthalate (DOP), propylene glycol, and isothiazolinone preservatives in sequence, stirring at 250 rpm for 10 minutes until homogeneous after each addition, for comparison of environmental friendliness and flexibility differences.

[0046] Comparative Example 2

[0047] The conventional ammonia neutralization process in existing technologies was simulated, with the following raw material weight percentages: 80.00% aqueous acrylic emulsion (solid content ≥45%), 0.75% alkali-swelling thickener, 6.00% dipropylene glycol dibenzoate, 5.60% deionized water, 3.50% glycerin, 3.00% propylene glycol, 0.95% isothiazolinone preservative, and 0.20% 25% ammonia. Preparation process: The formulated amount of aqueous acrylic emulsion was added to the reactor, and stirring was started and adjusted to 250 rpm. The mixture of alkali-swelling thickener and deionized water was slowly added, and after the addition was complete, stirring was maintained at 250 rpm for 30 minutes. 25% ammonia was added, and stirring was continued at 250 rpm for 90 minutes. Glycerin, dipropylene glycol dibenzoate, propylene glycol, and isothiazolinone preservative were added sequentially, and after each addition, stirring was maintained at 250 rpm for 10 minutes until homogeneous. This was used to compare differences in storage stability and transfer efficiency.

[0048] In the above embodiments, the 2-amino-2-methyl-1-propanol used was AMP-95, which is a mixture of 95% 2-amino-2-methyl-1-propanol and 5% water. The plasticizing functional additive used was Additive 988, which is dipropylene glycol dibenzoate; it was sourced from Eastman Chemical Company, USA. The preservative used was Preservative DB20, which is a 20% aqueous solution of 2,2-dibromo-3-cyanopropionamide (DBNPA).

[0049] Performance testing

[0050] The products obtained in Examples 1-4 and Comparative Examples 1-2 were subjected to performance testing. The testing methods included:

[0051] 1. Environmental performance testing

[0052] VOC content determination: Gas chromatography is used. Equal amounts of sample are injected into the chromatograph to detect the total amount of volatile organic compounds in the sample, expressed in g / L. The lower the value, the better the environmental friendliness.

[0053] Phthalate plasticizer detection: High performance liquid chromatography (HPLC) is used. After the sample is dissolved and filtered, the filtrate is injected into the chromatograph to detect the content of phthalate esters. The detection limit is set at ≤0.1%. If no detection is found, it meets the environmental protection requirements.

[0054] 2. Mechanical property testing of the adhesive film

[0055] Elongation at break (flexibility): The sample is evenly coated on a flat mold and dried to form a standard film with a thickness of 0.5 mm. The film is cut into standard tensile specimens with a cutter and stretched at a constant speed through a tensile testing machine until it breaks. The elongation at break is recorded and the elongation at break is calculated (in %). The higher the value, the better the flexibility of the film and the less brittle it is.

[0056] Aging resistance (accelerated at 50℃): Take the above standard film and place it in a 50℃ constant temperature oven and seal it for 90 days; after taking it out, restore it to room temperature and measure the elongation after aging according to the elongation at break test method, and calculate the aging resistance retention rate (retention rate = (elongation after aging / initial elongation) × 100%). The higher the retention rate, the better the long-term performance stability of the film.

[0057] 3. Transfer effect test

[0058] Transfer clarity: A standard image card with 10 levels of detail (including fine elements such as hair, 0.1mm thick text edges, and gradient patterns) is used. The sample is evenly applied to the surface of the image card, adhered to the target substrate (glass / wood), and constant pressure is applied. After the film dries, the original paper is peeled off. Three professionals visually score the transferred image detail (1 to 10 points, where 10 points means all details are completely clear, without blurring or missing, and 1 point means all details are completely lost). The average score of the three people is taken as the final result.

[0059] Transfer success rate: 50 repeatable transfer tests were conducted, 25 of which used glass as the substrate and 25 used wood as the substrate. Each test was performed according to the above transfer operation. The number of complete transfers was counted (judgment criteria: no image damage, no missing edges, no obvious bubbles). The transfer success rate was calculated (success rate = (number of complete transfers / 50) × 100%). A higher success rate indicates better operational fault tolerance and effect stability.

[0060] 4. Storage stability test

[0061] Viscosity change rate: The initial viscosity of the sample was measured at 25℃ and 100 rpm using an NDJ-5S rotational viscometer. The sample was then sealed and stored at room temperature for 6 months, and the viscosity was measured again. The viscosity change rate was calculated (change rate = (viscosity after storage - initial viscosity) / initial viscosity × 100%). The lower the change rate, the more stable the system is during storage, with no obvious stratification or flocculation.

[0062] pH value change: The initial pH value of the sample was measured using a pH meter with an accuracy of 0.01. The pH value was measured again after the sample was stored at room temperature for 6 months. The pH value change was calculated (change = pH after storage - initial pH). The smaller the change, the more stable the neutralization system is, which can avoid the effect of pH fluctuation on the use.

[0063] The specific test results are shown in the table below:

[0064]

[0065] Experimental results:

[0066] Environmental Performance: The embodiments of this invention are comprehensively superior to those of traditional solutions. The VOC content of embodiments 1-4 is controlled at 37-39 g / L, and no harmful phthalic plasticizers are detected, meeting the requirements of modern green production and use. In contrast, Comparative Example 1 not only has a VOC content of 42 g / L, but also contains 5.8% phthalic substances, posing a significant environmental risk. Comparative Example 2, due to the high volatility of ammonia, has a VOC content that further increases to 45 g / L, exhibiting the worst environmental performance. This indicates that the combination of dipropylene glycol dibenzoate and 2-amino-2-methyl-1-propanol used in this invention can fundamentally solve the environmental defects of traditional photo transfer adhesives.

[0067] Mechanical properties of the film: The examples show significant advantages in flexibility and aging resistance. The elongation at break of the films in Examples 1-4 are all ≥280%, and the aging resistance retention rate is ≥92%. Among them, the elongation at break of Examples 1 and 4 reach 320% and 325% respectively, and the performance degradation after aging is less than 5%, which can effectively prevent the transferred images from becoming brittle and cracking when the temperature changes or when stored for a long time. In Comparative Example 1, due to the poor compatibility between the phthalic plasticizer and the water-based acrylic emulsion, the elongation at break is only 220%, and the retention rate after aging drops sharply to 75%. Long-term use is prone to film damage and image detachment. Although the initial elongation at break of Comparative Example 2 reaches 300%, the ammonia water causes insufficient system stability, and the retention rate after aging is only 80%, which still cannot meet the requirements for long-term use.

[0068] Transfer Effect: The examples demonstrate superior clarity and success rate, with higher operational tolerance. Examples 1, 3, and 4 all achieved a transfer clarity score of 10 and a transfer success rate ≥97%. Example 4, due to extended stirring and neutralization time, resulted in more uniform mixing and further improved the transfer success rate to 99%, ensuring stable results even for ordinary users. Example 2, with a reduction in dipropylene glycol dibenzoate to 5.00%, slightly weakened plasticizing and solubilizing effects, resulting in a clarity score of 9 and a success rate of 96%, but still significantly better than the comparative example. Comparative Example 1, due to poor affinity between the plasticizer and ink, showed significant loss of image details, resulting in a clarity score of only 7 and a success rate of 82%. Comparative Example 2, due to pH fluctuations during storage leading to uneven film formation, achieved a clarity score of 8 and a success rate of 88%. It is evident that the formulation and process control of this invention maximize the integrity and stability of image transfer and broaden the operational window.

[0069] Storage Stability: The examples are suitable for large-scale production, with better batch consistency. The viscosity change rate of Examples 1-4 is ≤5.0%, and the pH change is ≤0.3. Among them, Example 4, due to more thorough mixing of components, has a viscosity change rate of only 3.8% and a pH change of 0.1, and can still maintain a stable state after 6 months of storage without stratification or flocculation. Comparative Example 2, due to the volatility of ammonia, has a viscosity change rate of 12.5% ​​and a pH change of 0.8 after 6 months of storage, and some samples show slight stratification, which cannot guarantee the batch use effect. Although the viscosity change rate of Comparative Example 1 is 6.8%, the plasticizer migration leads to the degradation of film performance, making it unsuitable for long-term storage. This shows that the formulation and process design of the present invention can effectively ensure the storage stability of the product and meet the needs of large-scale industrial production and long-term inventory.

[0070] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A photo transfer adhesive, characterized in that, It consists of the following raw materials by weight percentage: The composition includes 75%–85% acrylic emulsion, 0.5%–1.0% alkali-swelling thickener, 0.1%–0.3% 2-amino-2-methyl-1-propanol, 5.0%–6.0% deionized water, 3.0%–4.0% glycerol, 5.0%–7.0% dipropylene glycol dibenzoate, 2.5%–3.5% propylene glycol, and 0.8%–1.0% preservative, with the total weight percentage of all raw materials being 100%.

2. The photo transfer adhesive according to claim 1, characterized in that, It consists of the following raw materials by weight percentage: Acrylic emulsion 78%–82%, alkali-swelling thickener 0.6%–0.9%, 2-amino-2-methyl-1-propanol 0.15%–0.25%, deionized water 5.3%–5.8%, glycerin 3.2%–3.8%, dipropylene glycol dibenzoate 5.5%–6.5%, propylene glycol 2.7%–3.3%, preservative 0.85%–0.95%.

3. The photo transfer adhesive according to claim 1, characterized in that, It consists of the following raw materials by weight percentage: Acrylic emulsion 80.00%, alkali-swelling thickener 0.75%, 2-amino-2-methyl-1-propanol 0.20%, deionized water 5.60%, glycerin 3.50%, dipropylene glycol dibenzoate 6.00%, propylene glycol 3.00%, preservative 0.95%.

4. The photo transfer adhesive according to claim 1, characterized in that, The dipropylene glycol dibenzoate is a highly solubilized plasticizer.

5. The photo transfer adhesive according to claim 1, characterized in that, The preservative is an isothiazolinone preservative.

6. A method for preparing the phototransfer adhesive as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Add the prescribed amount of acrylic emulsion to the reactor and start stirring; S2: While stirring, slowly and evenly add the mixture consisting of the prescribed amount of alkali-swellable thickener and deionized water; S3: After the addition is complete, continue stirring for 20-40 minutes; S4: Slowly add the prescribed amount of 2-amino-2-methyl-1-propanol, and continue stirring for 60-120 minutes after the addition is complete; S5: Add the prescribed amounts of glycerol, dipropylene glycol dibenzoate, propylene glycol and preservative in sequence, and stir to mix evenly.

7. The method according to claim 6, characterized in that, In step S2, the mixture is added over a period of 10 to 15 minutes.

8. The method according to claim 6, characterized in that, The stirring speed in steps S1, S2, S4 and S5 is 200-400 rpm.

9. The method according to claim 6, characterized in that, In step S5, the order of adding each material is as follows: first add glycerin, then add dipropylene glycol dibenzoate, then add propylene glycol, and finally add the preservative. After each material is added, it is necessary to stir for 5 to 10 minutes until it is evenly mixed before adding the next material.

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