Glue for cold stamping process on non-coated paper as well as preparation method and application of glue

Abstract

The invention relates to glue for a cold stamping process on non-coated paper and a preparation method and application thereof.The glue comprises, by weight, 50%-55% of acrylate copolymer, 10%-15% of filler, 6%-10% of tackifier, 20%-28% of diluent and the balance auxiliaries, and the auxiliaries comprise, by weight, 1.2%-1.5% of flatting agent, 0.5%-0.7% of defoaming agent, 0.5%-1.5% of defoaming agent, 0.5%-1.5% of defoaming agent, 0.5%-1.5% of defoaming agent and the balance water. The cross-linking agent accounts for 1.5%-2% of the total weight, the coupling agent accounts for 1%-1.5% of the total weight, the antioxidant accounts for 0.2%-0.5% of the total weight, and the viscosity of the glue at 25 DEG C is 6000-7000 cps. When the glue is used for directly cold-ironing non-coated paper, air holes can be reduced, and the quality of cold-ironed printed matters is improved.

Description

Technical Field

[0001] The invention relates to the technical field of printing, and in particular to glue for cold stamping process on non-coated paper and a preparation method and application thereof. Background Art

[0002] Cold stamping is a hot stamping technology that is performed at room temperature. It is named after the traditional hot stamping technology that requires high temperature heating. The cold stamping process is to transfer the hot stamping material to the surface of the substrate directly on the printing machine using glue. In this process, there is no need for high temperature heating to melt the glue, thus achieving the hot stamping effect at room temperature or relatively low temperature.

[0003] Cold stamping has certain requirements on the surface smoothness of the substrate, and a rough substrate may affect the stamping effect. According to whether the paper has been coated, it is divided into coated paper and uncoated paper. Coated paper is a paper that is coated with one or more layers of coating (such as a white mineral coating) on ​​the base paper, and then dried, calendered, etc. to obtain a smooth and flat surface with high gloss. Uncoated paper is paper that has not been coated, and its surface is rough and has a convex and concave feel. During cold stamping, the ink absorption capacity of coated paper is relatively weak, and it is easier to obtain a clear pattern effect. It has a high degree of color reproduction and strong detail expression. Uncoated paper will absorb ink. Due to the uneven surface, the speed and amount of ink absorption in different parts are inconsistent, resulting in uneven ink distribution and problems such as pores. Figure 1 As shown, the positions indicated by circles and arrows are pores, and the presence of pores seriously affects the quality and aesthetics of printed products.

[0004] Chinese patent application CN116948458A discloses a water-based UV cold stamping ink and a hot stamping method thereof, which are composed of the following raw materials in weight percentage: special water-based resin: 80% to 95%, humectant: 3% to 15%, photoinitiator: 1% to 3%, leveling agent: 1% to 3%; wetting agent: 1% to 3%, other additives: 3% to 6%, the total of the above raw materials is 100%, wherein the special water-based resin is a thermoplastic water-based resin with surface drying properties, the humectant is used to moisten and promote the film formation of the water-based resin, including one or more of ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, methyl propylene glycol, glycerol, and hexylene glycol; the advantage is that the VOC emission of the water-based UV cold stamping ink is close to 0, it is green, environmentally friendly, non-toxic, has no irritating odor, and is non-corrosive, and the hot stamping method using the water-based UV cold stamping ink is simple and effective, meeting the requirements of short-run small batch orders and differentiated hot stamping. However, this water-based UV cold stamping ink still cannot solve the problem of pores during cold stamping.

[0005] Therefore, how to effectively reduce or avoid the occurrence of excessive cold-ironing pores on uncoated paper has been an urgent problem to be solved in the art. Summary of the invention

[0006] The purpose of the present invention is to overcome the problem of many cold-foil pores on existing uncoated paper, provide a glue for cold-foil process on uncoated paper and its preparation method and application, and reduce the number of pores on cold-foil printed products by adjusting the formula of the glue.

[0007] The specific plan is as follows:

[0008] A glue for cold stamping process on non-coated paper comprises, by weight percentage: 50%-55% of acrylate copolymer, 10%-15% of filler, 6%-10% of tackifier, 20-28% of diluent, and the balance is auxiliary agents, wherein the auxiliary agents include: a leveling agent accounting for 1.2%-1.5% of the total weight, a defoaming agent accounting for 0.5%-0.7% of the total weight, a cross-linking agent accounting for 1.5%-2% of the total weight, a coupling agent accounting for 1%-1.5% of the total weight, and an antioxidant accounting for 0.2%-0.5% of the total weight. The viscosity of the glue at 25°C is 6000-7000cps.

[0009] Furthermore, the acrylic acid ester copolymer is obtained by copolymerization of methyl acrylate, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate and acrylic acid.

[0010] Furthermore, the acrylic acid ester copolymer is prepared from the following raw materials in terms of mass percentage:

[0011]

[0012] Furthermore, the filler is a mixture of nano silicon dioxide and nano calcium carbonate, wherein the nano silicon dioxide accounts for 9-12% of the total weight, and the nano calcium carbonate accounts for 0.5-5% of the total weight.

[0013] Furthermore, the tackifier is a mixture of rosin resin and terpene resin, the rosin resin accounts for 3-8% of the total weight, and the terpene resin accounts for 3-8% of the total weight.

[0014] Furthermore, the diluent is a mixture of ethyl acetate and propylene glycol methyl ether acetate, wherein the ethyl acetate accounts for 15-20% of the total weight and the propylene glycol methyl ether acetate accounts for 5-8% of the total weight.

[0015] Furthermore, the leveling agent is a compound of an organic silicon leveling agent and a fluorocarbon leveling agent in a mass ratio of 1:1-2.

[0016] Furthermore, the defoamer is a polyether defoamer, the crosslinker is an aziridine crosslinker, the coupling agent is an aminosilane coupling agent, and the antioxidant is a hindered phenol antioxidant and a phosphite antioxidant compounded in a mass ratio of 1-2:1.

[0017] The present invention also protects a method for preparing the glue for the cold stamping process on uncoated paper, wherein the raw materials are obtained in proportion, and acrylate copolymer, nano-silicon dioxide, nano-calcium carbonate, rosin resin, terpene resin, ethyl acetate, and propylene glycol methyl ether acetate are sequentially added into a stirring device, the stirring speed is controlled to be 100-10000 rpm, the stirring time is 20-60 minutes, the mixture is fully mixed, and then an auxiliary agent is added, and the stirring is continued for 10-30 minutes.

[0018] The present invention also protects the use of the glue of the cold stamping process on non-coated paper for cold stamping on non-coated paper.

[0019] Beneficial effects:

[0020] The invention effectively reduces the pore problem during direct cold stamping on non-coated paper by adjusting the glue formula, thereby improving the quality and aesthetics of printed products. The glue preparation operation is simple, the cost is low, the printing improvement effect is significant, and it has broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings will be briefly introduced below. Obviously, the accompanying drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0022] Figure 1 It is a cold perm effect diagram provided by the background technology;

[0023] Figure 2 This is a cold stamping effect diagram of white kraft paper provided by an embodiment of the present invention;

[0024] Figure 3 This is a cold stamping effect diagram of art paper (zero ash cotton paper) provided by an embodiment of the present invention;

[0025] Figure 4 This is a cold stamping effect diagram of 100% recycled paper provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. In the examples, those without specifying specific techniques or conditions are carried out according to the techniques or conditions described in the literature in this area or according to the product specification. Those without specifying the manufacturer of reagents or instruments used are all conventional products that can be obtained commercially. In the following examples, if not clearly stated, "%" refers to weight percentage.

[0027] The test methods and equipment for the following test items are shown in Table 1:

[0028] Table 1 Test methods and equipment for test items

[0029]

[0030] The main reagents used include:

[0031] Acrylate copolymer: obtained by copolymerization of acrylate and acrylic acid, wherein the amount range of each raw material is shown in Table 2. The preparation method includes: obtaining by copolymerization of methyl acrylate, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate and acrylic acid, and adding initiator, chain transfer agent, inhibitor and solvent during the reaction. Specifically, the following process can be used:

[0032] Material preparation: weigh the raw materials according to Table 2, mix the weighed methyl acrylate, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate and acrylic acid in a clean container to prepare a monomer mixture; dissolve azobisisobutyronitrile in an appropriate amount of toluene to prepare an initiator solution, and place it in a dropping funnel; take dodecyl mercaptan and hydroquinone and add them to toluene, stir and dissolve them, and obtain a toluene solution containing a chain transfer agent and an inhibitor. In a specific embodiment, the amount of raw materials used is: methyl acrylate (MA) 22%, butyl acrylate (BA) 32%, methyl methacrylate (MMA) 15%, hydroxyethyl acrylate (HEA) 15%, acrylic acid (AA) 8%, initiator (azobisisobutyronitrile AIBN) 0.8%, chain transfer agent (dodecyl mercaptan) 0.2%, inhibitor (hydroquinone) 0.05%, solvent (toluene) balance.

[0033] Initiation reaction: add some toluene to the reaction vessel, stir at 150-250r / min, and heat to 70-80°C in a constant temperature water bath. After the temperature stabilizes, add toluene solution containing chain transfer agent and inhibitor, stir evenly, and then slowly drip initiator solution to initiate the reaction.

[0034] Adding monomers and polymerization: 15-30 minutes after the reaction is initiated, slowly add the monomer mixture, control the dropping speed to make the reaction stable, and finish the dropping in 2-3 hours. After the dropping is completed, keep the temperature for 1-2 hours to ensure that the monomer polymerization is complete.

[0035] Post-treatment: After the reaction is finished, stop heating, cool naturally to room temperature, filter and remove impurities to obtain a pure copolymer solution. If the product viscosity is too high, add toluene to dilute and stir.

[0036] Table 2 Raw material usage for preparing acrylic copolymers / mass percentage

[0037] Element Content range Methyl acrylate (MA) 22％-26％ Butyl acrylate (BA) 28％-32％ Methyl Methacrylate (MMA) 15％-18％ Hydroxyethyl acrylate (HEA) 12％-15％ Acrylic acid (AA) 8％-10％ Initiator (such as azobisisobutyronitrile AIBN) 0.8％-1.2％ Chain transfer agent (such as dodecyl mercaptan) 0.1％-0.5％ Inhibitors (such as hydroquinone) 0.01％-0.05％ Solvent (such as toluene) margin total 100％

[0038] Nano-silicon dioxide, particle size 20-50 nanometers;

[0039] Nano calcium carbonate, particle size 30-60 nanometers;

[0040] Leveling agent: Use silicone leveling agent and fluorocarbon leveling agent in a 1:1 mass ratio;

[0041] Defoaming agent: Use polyether defoaming agent;

[0042] Cross-linking agent: Aziridine cross-linking agent is used;

[0043] Coupling agent: γ-aminopropyltriethoxysilane (KH550);

[0044] Antioxidant: Hindered phenol antioxidant 1010 and phosphite antioxidant 168 are compounded in a mass ratio of 2:1.

[0045] Example 1

[0046] A glue for cold stamping process on uncoated paper, the amount of each raw material is shown in Table 3, and the preparation method comprises the following steps: obtaining each raw material according to a proportion, adding acrylate copolymer, nano silicon dioxide, nano calcium carbonate, rosin resin, terpene resin, ethyl acetate, and propylene glycol methyl ether acetate to a stirring device in sequence, controlling the stirring speed to 1000 rpm, the stirring time to 30 minutes, fully mixing, then adding an auxiliary agent, and continuing stirring for 10 minutes to obtain glue.

[0047] Table 3 Glue raw material dosage table / weight percentage

[0048]

[0049] Comparative Example 1

[0050] Refer to Example 1, except that the acrylate copolymer is replaced by methyl acrylate of equal mass.

[0051] Comparative Example 2

[0052] Referring to Example 1, the difference is that the filler is different, and the filler in Example 1 is replaced by nano-silicon dioxide of the same mass.

[0053] Comparative Example 3

[0054] Refer to Example 1, the difference is that the diluent is different, and the diluent in Example 1 is replaced by ethyl acetate of equal mass.

[0055] Performance Testing

[0056] The viscosity, drying time and bonding strength of the glue prepared above were tested at 25°C. The results are shown in Table 4.

[0057] Table 4 Glue test results

[0058] sample Viscosity / cps Drying time / minute <![CDATA[Bond strength / N / cm 2 > Temperature resistance / ℃ Example 1 6000 12 Greater than or equal to 2.5 -20 to 60 Example 2 6500 13 Greater than or equal to 2.5 -20 to 60 Example 3 7000 14 Greater than or equal to 2.5 -20 to 60 Example 4 6200 11 Greater than or equal to 2.8 -25 to 65 Example 5 6800 12.5 Greater than or equal to 2.7 -22 to 63 Comparative Example 1 5000 15 1.8 -10 to 50 Comparative Example 2 8000 18 2.2 -15 to 55 Comparative Example 3 4500 10 2.0 -5 to 45

[0059] Cold stamping test

[0060] Different types of uncoated paper were selected, all with a gram weight of 150G. The paper was pre-treated by surface cleaning, flattening, back cover, etc., and then cold stamping was performed. The glue prepared in the embodiment and comparative example was evenly coated on the surface of the paper. The pressure of the cold stamping equipment was controlled to be 3-5MPa, the temperature was 80-100°C, and the cold stamping speed was 3-5m / min. The specific conditions are shown in Table 5. Then, the paper was dried to obtain a finished product, such as Figure 2-4 shown.

[0061] The appearance of the finished product was observed with the naked eye, and the results are shown in Table 5. No obvious pores means that there are no pores visible to the naked eye within the cold stamping pattern of A4 paper size.

[0062] Table 5 Cold stamping test results

[0063]

[0064]

[0065] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0066] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0067] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A glue for cold stamping process on uncoated paper, characterized by: The invention comprises, by weight percentage, 50%-55% of acrylate copolymer, 10%-15% of filler, 6%-10% of tackifier, 20-28% of diluent, and the balance of auxiliary agents, wherein the auxiliary agents comprise: 1.2%-1.5% of leveling agent, 0.5%-0.7% of defoamer, 1.5%-2% of cross-linking agent, 1%-1.5% of coupling agent, and 0.2%-0.5% of antioxidant. The viscosity of the glue is 6000-7000cps at 25°C.

2. The glue for cold stamping process on uncoated paper according to claim 1, characterized in that: The acrylic acid ester copolymer is obtained by copolymerization of methyl acrylate, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate and acrylic acid.

3. The glue for cold stamping process on uncoated paper according to claim 2, characterized in that: The acrylic acid ester copolymer is prepared from the following raw materials according to mass percentage:

4. The glue for cold stamping process on uncoated paper according to claim 1, characterized in that: The filler is a mixture of nano silicon dioxide and nano calcium carbonate, wherein the nano silicon dioxide accounts for 9-12% of the total weight and the nano calcium carbonate accounts for 0.5-5% of the total weight.

5. The glue for cold stamping process on uncoated paper according to claim 1, characterized in that: The tackifier is a mixture of rosin resin and terpene resin, wherein the rosin resin accounts for 3-8% of the total weight, and the terpene resin accounts for 3-8% of the total weight.

6. The glue for cold stamping process on uncoated paper according to claim 1, characterized in that: The diluent is a mixture of ethyl acetate and propylene glycol methyl ether acetate, wherein the ethyl acetate accounts for 15-20% of the total weight and the propylene glycol methyl ether acetate accounts for 5-8% of the total weight.

7. The glue for cold stamping process on uncoated paper according to claim 1, characterized in that: The leveling agent is a compound of an organic silicon leveling agent and a fluorocarbon leveling agent in a mass ratio of 1:1-2.

8. The glue for cold stamping process on uncoated paper according to claim 1, characterized in that: The defoamer is a polyether defoamer, the crosslinker is an aziridine crosslinker, the coupling agent is an aminosilane coupling agent, and the antioxidant is a hindered phenol antioxidant and a phosphite antioxidant compounded in a mass ratio of 1-2:

1.

9. The method for preparing glue for cold stamping process on uncoated paper according to any one of claims 1 to 8, characterized in that: Obtain each raw material in proportion, add acrylate copolymer, nano-silicon dioxide, nano-calcium carbonate, rosin resin, terpene resin, ethyl acetate, and propylene glycol methyl ether acetate into a stirring device in sequence, control the stirring speed to 100-10000rpm, the stirring time to 20-60min, mix well, then add the additive, and continue stirring for 10-30min.

10. Use of the glue for cold stamping process on uncoated paper according to any one of claims 1 to 8 on uncoated paper.

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