1. A three-dimensional crystal grain printing process is characterized in that: the method comprises the following steps:

s1: preparing special surface UV ink and special bottom UV ink;

s2: placing a printing piece in an environment with humidity of 10-20%, and coating maleic acid liquid on the surface of the printing piece to form an ink base layer;

s3: the printing piece coated with the ink base layer in the step S2 is sent to the environment with the temperature of 50-60 ℃ for drying;

s4: printing the bottom layer UV ink prepared in the step S1 on the surface of the ink base layer of the printing element dried in the step S3 in a screen printing mode, and carrying out UV curing;

s5: printing the surface layer UV ink prepared in the step S1 on the surface of the bottom layer UV ink of the printing piece in the step S4 in a screen printing mode, and carrying out UV curing;

s6: and (4) heating and drying the printing piece finally obtained in the step (S5), and standing for 18-25 h at the ventilated normal temperature.

2. The stereographic grain printing process of claim 1, wherein: the surface layer UV ink in the step S1 comprises the following components in percentage by weight:

3. the stereographic grain printing process of claim 1, wherein: the underlayer UV ink in the step S1 comprises the following components in percentage by weight:

4. the stereographic printing process according to claim 2 or 3, wherein: the preparation process of the surface layer UV ink and the bottom layer UV ink comprises the following steps:

a: adding raw materials and stirring;

b: b, rotationally grinding the raw materials stirred in the step a to a corresponding mesh number through a grinder, and uniformly spraying a proper amount of water in the grinding process;

c: and c, collecting and storing the ground raw materials in the step b for later use.

5. The stereographic grain printing process of claim 4, wherein: stirring for at least 30min in the step a.

6. The stereographic grain printing process of claim 4, wherein: and b, grinding the raw materials in the step b to a mesh number of 70-120.

7. The stereographic grain printing process of claim 4, wherein: when the UV ink of the bottom layer is subjected to screen printing in the step S4, the mesh of the used screen is between 70 and 180T; when the UV ink of the surface layer is used for screen printing in the step S5, the mesh of the screen is between 90 and 120T.

8. The stereographic grain printing process of claim 4, wherein: in step S6, drying is carried out by IR baking at a baking temperature of not less than 130 ℃.

9. The stereographic grain printing process of claim 4, wherein: when the UV ink of the bottom layer is cured in the step S4, the UV ink is curedThe chemical energy is set to 55 + -5 mj/cm²(ii) a In the step S5, when the UV ink on the surface layer is cured, the UV curing energy is set to 105 +/-5 mj/cm²。

10. The stereographic grain printing process of claim 4, wherein: after the step S4 is completed, the step S5 is performed at an interval of 3-5 min.

Background

The crystal grain printing is to print two different kinds of ink on the carried object in turn, and through curing treatment, grains are formed on the surface, which is mainly used for grain printing of paper. The quality of the printed crystal grains is related to the physical and chemical properties of each layer of printing ink, the material of the bearing object, the printing process and the selection of the printing mode. The grain lines prepared by the existing grain printing process are single in layer, easy to fall off and not stable enough in effect.

Disclosure of Invention

In view of the defects in the prior art, the present invention is directed to a three-dimensional grain printing process, which solves one or more of the problems set forth above.

In order to achieve the purpose, the invention provides the following technical scheme:

a three-dimensional crystal grain printing process comprises the following steps:

s1: preparing special surface UV ink and special bottom UV ink;

s2: placing a printing piece in an environment with humidity of 10-20%, and coating maleic acid liquid on the surface of the printing piece to form an ink base layer;

s3: the printing piece coated with the ink base layer in the step S2 is sent to the environment with the temperature of 50-60 ℃ for drying;

s4: printing the bottom layer UV ink prepared in the step S1 on the surface of the ink base layer of the printing element dried in the step S3 in a screen printing mode, and carrying out UV curing;

s5: printing the surface layer UV ink prepared in the step S1 on the surface of the bottom layer UV ink of the printing piece in the step S4 in a screen printing mode, and carrying out UV curing;

s6: and (4) heating and drying the printing piece finally obtained in the step (S5), and standing for 18-25 h at the ventilated normal temperature.

Further, the surface layer UV ink in step S1 includes the following components in percentage by weight:

further, the underlayer UV ink in the step S1 includes the following components by weight percentage:

further, the preparation process of the surface layer UV ink and the bottom layer UV ink comprises the following steps:

a: adding raw materials and stirring;

b: b, rotationally grinding the raw materials stirred in the step a to a corresponding mesh number through a grinder, and uniformly spraying a proper amount of water in the grinding process;

c: and c, collecting and storing the ground raw materials in the step b for later use.

Further, stirring in step a for at least 30 min.

Further, the raw materials in the step b are ground to 70-120 meshes.

Further, when the UV ink of the bottom layer is subjected to screen printing in the step S4, the mesh of the used screen is between 70 and 180T; when the UV ink of the surface layer is used for screen printing in the step S5, the mesh of the screen is between 90 and 120T.

Further, in step S6, drying is performed by IR baking at a baking temperature of not less than 130 ℃.

Further, in step S4, when the UV ink on the bottom layer is cured, the UV curing energy is set to 55 +/-5 mj/cm 2; in step S5, when the UV ink on the surface layer is cured, the UV curing energy is set to 105 + -5 mj/cm 2.

Further, after the completion of step S4, it is necessary to perform step S5 again at an interval of 3-5 min.

In conclusion, the invention has the following beneficial effects:

the specially prepared surface UV ink and bottom UV ink can have a network hierarchical structure with higher crosslinking degree and higher activity, so that the crystal grain hierarchical feeling formed after heating and mutual dissolution is stronger; the printed crystal grain has uniform lines and stable effect and is not easy to fall off; after the ink base layer is treated, two layers of UV ink are coated, so that the stability of the grain lines can be improved.

Drawings

FIG. 1 is a flow chart of a stereographic grain printing process according to the present invention;

FIG. 2 is a flow chart of a UV ink preparation process of the present invention

Detailed Description

The present invention is described in further detail below with reference to FIGS. 1-2.

Example 1:

a three-dimensional crystal grain printing process comprises the following steps:

s1, preparing special surface layer UV ink and bottom layer UV ink:

the surface UV ink comprises the following components in percentage by weight:

the bottom layer UV ink comprises the following components in percentage by weight:

the preparation process of the surface layer UV ink and the bottom layer UV ink comprises the following steps:

a: adding raw materials, stirring, and stirring for at least 30 min;

b: b, grinding the stirred raw materials in the step a to 100 meshes by a grinding machine in a rotating way, and uniformly spraying a proper amount of water in the grinding process, wherein the water is sprayed only for promoting the stirring and the grinding, but not for supplementing the two ink components;

c: c, collecting and storing the ground raw materials in the step b in a centralized manner for later use;

s2: placing a printing piece in an environment with the humidity of 15%, and coating maleic acid liquid on the surface of the printing piece to form an ink base layer;

s3: the printing piece coated with the ink base layer in the step S2 is sent to an environment with the temperature of 55 ℃ for drying;

s4: printing the bottom layer UV ink prepared in the step S1 on the surface of the ink base layer of the printing element dried in the step S3 in a screen printing mode, and carrying out UV curing;

when the bottom layer UV ink is used for screen printing, the mesh of the used screen is between 120T;

when the bottom layer UV ink is cured, the UV curing energy is set to be 55mj/cm²；

Standing for 3 min;

s5: printing the surface layer UV ink prepared in the step S1 on the surface of the bottom layer UV ink of the printing piece in the step S4 in a screen printing mode, and carrying out UV curing;

when the UV printing ink on the surface layer is used for screen printing, the mesh of the used screen is between 100T;

wherein, when the UV ink on the surface layer is cured, the UV curing energy is set to be 105mj/cm²；

S6: and (4) heating and drying the printing piece finally obtained in the step (S5) in an IR baking mode, wherein the baking temperature is not less than 130 ℃, the baking time is adjusted according to the printing area of the printing piece, the larger the area is, the longer the baking time is, and after the baking is finished, the printing piece is placed at the ventilating normal temperature and stands for 18 h.

Example 2:

a three-dimensional crystal grain printing process comprises the following steps:

s1, preparing special surface layer UV ink and bottom layer UV ink:

the surface UV ink comprises the following components in percentage by weight:

the bottom layer UV ink comprises the following components in percentage by weight:

the preparation process of the surface layer UV ink and the bottom layer UV ink comprises the following steps:

a: adding raw materials, stirring, and stirring for at least 30 min;

b: b, grinding the stirred raw materials in the step a to 100 meshes by a grinding machine in a rotating way, and uniformly spraying a proper amount of water in the grinding process, wherein the water is sprayed only for promoting the stirring and the grinding, but not for supplementing the two ink components;

c: c, collecting and storing the ground raw materials in the step b in a centralized manner for later use;

s2: placing a printing piece in an environment with the humidity of 15%, and coating maleic acid liquid on the surface of the printing piece to form an ink base layer;

s3: the printing piece coated with the ink base layer in the step S2 is sent to an environment with the temperature of 55 ℃ for drying;

s4: printing the bottom layer UV ink prepared in the step S1 on the surface of the ink base layer of the printing element dried in the step S3 in a screen printing mode, and carrying out UV curing;

when the bottom layer UV ink is used for screen printing, the mesh of the used screen is between 120T;

when the bottom layer UV ink is cured, the UV curing energy is set to be 55mj/cm²；

Standing for 3 min;

s5: printing the surface layer UV ink prepared in the step S1 on the surface of the bottom layer UV ink of the printing piece in the step S4 in a screen printing mode, and carrying out UV curing;

when the UV printing ink on the surface layer is used for screen printing, the mesh of the used screen is between 100T;

wherein, when the UV ink on the surface layer is cured, the UV curing energy is set to be 105mj/cm²；

S6: and (4) heating and drying the printing piece finally obtained in the step (S5) in an IR baking mode, wherein the baking temperature is not less than 130 ℃, the baking time is adjusted according to the printing area of the printing piece, the larger the area is, the longer the baking time is, and after the baking is finished, the printing piece is placed at the ventilating normal temperature and stands for 18 h.

Example 3

A three-dimensional crystal grain printing process comprises the following steps:

s1, preparing special surface layer UV ink and bottom layer UV ink:

the surface UV ink comprises the following components in percentage by weight:

the bottom layer UV ink comprises the following components in percentage by weight:

the preparation process of the surface layer UV ink and the bottom layer UV ink comprises the following steps:

a: adding raw materials, stirring, and stirring for at least 30 min;

b: b, grinding the stirred raw materials in the step a to 100 meshes by a grinding machine in a rotating way, and uniformly spraying a proper amount of water in the grinding process, wherein the water is sprayed only for promoting the stirring and the grinding, but not for supplementing the two ink components;

c: c, collecting and storing the ground raw materials in the step b in a centralized manner for later use;

s2: placing a printing piece in an environment with the humidity of 15%, and coating maleic acid liquid on the surface of the printing piece to form an ink base layer;

s3: the printing piece coated with the ink base layer in the step S2 is sent to an environment with the temperature of 55 ℃ for drying;

s4: printing the bottom layer UV ink prepared in the step S1 on the surface of the ink base layer of the printing element dried in the step S3 in a screen printing mode, and carrying out UV curing;

when the bottom layer UV ink is used for screen printing, the mesh of the used screen is between 120T;

when the bottom layer UV ink is cured, the UV curing energy is set to be 55mj/cm²；

Standing for 3 min;

s5: printing the surface layer UV ink prepared in the step S1 on the surface of the bottom layer UV ink of the printing piece in the step S4 in a screen printing mode, and carrying out UV curing;

when the UV printing ink on the surface layer is used for screen printing, the mesh of the used screen is between 100T;

wherein, when the UV ink on the surface layer is cured, the UV curing energy is set to be 105mj/cm²；

S6: and (4) heating and drying the printing piece finally obtained in the step (S5) in an IR baking mode, wherein the baking temperature is not less than 130 ℃, the baking time is adjusted according to the printing area of the printing piece, the baking time is slightly longer when the area is larger, and the printing piece is placed in a ventilating normal temperature place for standing for 18h after baking is finished.

A comparison was made in conjunction with a variety of crystallized printed articles currently on the market:

tests show that the grain effect is more stable and natural along with the rise of the temperature of IR baking, and the higher the temperature is, the better the effect is within the range of 130 +/-5 ℃; increasing the IR baking temperature excessively beyond the above range only degrades the quality of grain formation.

To UV printing ink layer, improve the ratio of principal ingredients in the printing ink, under the fashioned prerequisite of crystal grain not influencing for the printing ink layer attenuation makes the crystal grain line more meticulous.

And the two layers of printing ink interact to generate a swelling phenomenon, the coatings extrude and mix with each other along with the rise of temperature to generate an irregular grain effect, and due to the improvement of the components such as 1, 6-hexanediol diacrylate and the like in the formula, when the coatings are independently formed, the coatings have a network hierarchical structure with higher crosslinking degree inside, and are more 'three-dimensional' and clearly layered, and when the coatings extrude with each other, the three-dimensional effect is further enhanced, so that the finally formed grain structure is more distinct in level and full in three-dimensional effect, and the forming effect of the grains is enriched.

Before coating two layers of printing ink, the printing ink base layer is attached to the surface of a printing piece under a proper humidity environment, and is dried and solidified, so that the printing piece is firmly formed; the two layers of ink also react with the ink base layer to adhere to the substrate. Finally, the whole crystal grain is not easy to fall off from the printing piece.

When the two layers of printing ink are solidified, the two layers of printing ink are solidified by specific energy, and the effect of the grain lines is stable.

Tests show that when the screen printing is carried out, the effect that the lines are obviously observed is poor when the screen mesh is less than 100T, and obvious line faults can be caused when the difference value of the screen meshes of the two layers of printing ink is more than 20T.

Therefore, the product prepared by the three-dimensional crystal grain printing process in the embodiment 1-3 has the advantages of more distinct grain structure level, better three-dimensional sense, finer crystal grain grains, better crystal grain effect and the like.

Comparing the crystal grain paper obtained in examples 1 to 3 with the crystal grain products sold on the market (taking the crystal grain paper sold by Shantou Shanyu paper industry Co., Ltd as an example), wherein the basic conditions such as the area size of all the finished product paper, the material of the printing paper and the like are the same, namely only changing relevant step variables in the three-dimensional crystal grain printing process, such as conditions of ink components, curing energy and the like, and obtaining a conclusion after analysis, the table below shows:

TABLE 1

Detecting items	Example 1	Example 2	Example 3	Common crystal grain paper
					Visual inspection of grain appearance	Good effect	Good effect	Good effect	General effects
20 degree gloss	92％	89％	90％	70％
					Gloss at 45 degree observation	79％	75％	72％	43％
60 degree gloss	61％	55％	52％	31％
					Adhesion condition	Good effect	Good effect	Good effect	In general
Wear resistance	Is preferably used	Is preferably used	Is preferably used	In general
					Film thickness	7μm	8μm	8μm	12μm

As can be seen from table 1, the coating films of examples 1 to 3 are much smaller than those of the existing prints, the abrasion resistance and the adhesion ability are stronger than those of the existing prints, and the gloss is better when observed from different angles because of the network hierarchical structure with higher degree of crosslinking, wherein each performance of example 1 is the best, so example 1 is the best scheme among the three examples, and the ink components are the best mixture ratio.

It should be noted that the present embodiment is only for explaining the present invention, and the present invention is not limited thereto, and those skilled in the art can make modifications to the embodiment without inventive contribution as required after reading the present specification, but all the modifications are protected by patent law within the scope of the claims of the present invention.