阅读说明：本技术 一种瓦楞纸复合用胶及其制备方法 (Glue for compounding corrugated paper and preparation method thereof ) 是由 陆俊 姚成 于 2021-09-11 设计创作，主要内容包括：本发明涉及胶粘剂技术领域,具体公开了一种瓦楞纸复合用胶及其制备方法,包括以下重量份的原料：玉米淀粉250-350份、改性木薯淀粉40-60份、氢氧化钠9-12份、硼砂1-3份、膨润土2-6份、填料6-10份、催干剂4-6份、水1000-1300份；催干剂由山梨糖醇、聚丙烯酸钠以及聚乙烯醇组成,所述山梨糖醇、聚丙烯酸钠以及聚乙烯醇的重量比为1:(0.5-1):(1-2)；制备方法为：将500-600重量份的水加热至35-50℃,后加入玉米淀粉、改性木薯淀粉混合,混合均匀后,加入氢氧化钠继续混合均匀；60-80min后加入余量的水、硼砂混合均匀,得到第一混合物；后加入填料、催干剂、膨润土混合均匀,得到瓦楞纸复合用胶；本申请的瓦楞纸复合用胶具有干燥速度快的优点。(The invention relates to the technical field of adhesives, and particularly discloses an adhesive for compounding corrugated paper and a preparation method thereof, wherein the adhesive comprises the following raw materials in parts by weight: 350 parts of corn starch, 40-60 parts of modified cassava starch, 9-12 parts of sodium hydroxide, 1-3 parts of borax, 2-6 parts of bentonite, 6-10 parts of filler, 4-6 parts of drier and 1300 parts of water; the drier consists of sorbitol, sodium polyacrylate and polyvinyl alcohol, wherein the weight ratio of the sorbitol to the sodium polyacrylate to the polyvinyl alcohol is 1 (0.5-1) to 1-2; the preparation method comprises the following steps: heating 500 plus 600 parts by weight of water to 35-50 ℃, adding the corn starch and the modified cassava starch for mixing, adding the sodium hydroxide for continuously mixing uniformly after uniformly mixing; adding the balance of water and borax after 60-80min, and uniformly mixing to obtain a first mixture; then adding filler, drier and bentonite, and mixing uniformly to obtain the glue for compounding the corrugated paper; the glue for compounding the corrugated paper has the advantage of high drying speed.)

1. The glue for compounding the corrugated paper is characterized by comprising the following raw materials in parts by weight:

350 portions of corn starch 250-;

40-60 parts of modified cassava starch;

9-12 parts of sodium hydroxide;

1-3 parts of borax;

2-6 parts of bentonite;

6-10 parts of a filler;

5-8 parts of a drier;

1000 portions of water and 1300 portions of water;

the drier consists of sorbitol, sodium polyacrylate and polyvinyl alcohol, wherein the weight ratio of the sorbitol to the sodium polyacrylate to the polyvinyl alcohol is 1 (0.5-1) to 1-2.

2. A compound for corrugated paper as defined in claim 1 wherein the filler includes at least one of kaolin clay and walnut shell flour.

3. The corrugated paper composite glue of claim 1, wherein the modified tapioca starch is prepared by the following steps:

a1, mixing the cassava starch with water, adding the nonionic surfactant after uniformly mixing, and obtaining primary cassava starch after uniformly mixing;

a2, mixing the primary cassava starch and polyacrylamide at the temperature of 75-85 ℃, adding an initiator and a silane coupling agent after uniform mixing, drying and crushing after 1-3h to obtain the modified cassava starch.

4. The corrugated paper composite glue as claimed in claim 3, wherein the weight ratio of the tapioca starch, polyacrylamide and the nonionic surfactant is 1 (0.2-0.5) to (0.01-0.03).

5. The corrugated paper composite gum as claimed in claim 3, wherein in the step A1, the non-ionic surfactant comprises at least one of alkyl glycoside and polysorbate.

6. The corrugated paper composite glue according to claim 1, wherein the raw material of the corrugated paper composite glue further comprises 1-3 parts by weight of an accelerant, and the accelerant comprises at least one of eucalyptus powder and boron carbide.

7. The corrugated paper composite glue as claimed in claim 6, wherein the accelerant consists of eucalyptus powder and boron carbide in a weight ratio of 1 (1-2).

8. The method for preparing the glue for compounding corrugated paper as claimed in any one of claims 1 to 7, which is characterized by comprising the following preparation steps:

s1, heating 600 parts by weight of 500-50 ℃ water to 35-50 ℃, adding the corn starch and the modified tapioca starch, mixing uniformly, adding sodium hydroxide, and continuously mixing uniformly; adding the balance of water and borax after 60-80min, and uniformly mixing to obtain a first mixture;

and S2, adding the filler, the drier and the bentonite into the first mixture, and uniformly mixing to obtain the glue for compounding the corrugated paper.

9. The method of claim 8, wherein in step S2, the first mixture is mixed with 1-3 parts by weight of an accelerator, and the accelerator is mixed with the filler, the drier, and the bentonite.

Technical Field

The invention relates to the technical field of adhesives, in particular to an adhesive for compounding corrugated paper and a preparation method thereof.

Background

The composite glue for corrugated paper is an important adhesive in the production process of corrugated paper boards, mainly takes composite glue taking starch as a base material, and has the advantages of low price and wide source.

Chinese patent application with publication number CN101134881A and publication date 2008, 03 and 05 discloses a starch adhesive for producing high-strength water-resistant corrugated boards, which consists of the following raw materials in percentage by weight: 50-90 parts of water; 20-40 parts of starch; 0.5-3.5 parts of caustic soda; 0.1-0.2 part of suspending agent; 0.25-0.3 part of borax; 0.6-2.0 parts of bridging agent; the temperature of the water is 35-36 ℃.

Through above-mentioned correlation technique, although the moisture in the starch adhesive can effectively wet the corrugated paper, soften paper fibre, for the laminating process opening the passageway afterwards, because the moisture of infiltration corrugated paper fibre surface pore is more, lead to the corrugated paper water content great easily, the drying rate of adhesive is slower.

Disclosure of Invention

In order to improve the drying speed of the glue for compounding corrugated paper, the application provides the glue for compounding the corrugated paper and a preparation method thereof.

In a first aspect, the application provides a glue for compounding corrugated paper, which adopts the following technical scheme:

the glue for compounding the corrugated paper comprises the following raw materials in parts by weight:

350 portions of corn starch 250-;

40-60 parts of modified cassava starch;

9-12 parts of sodium hydroxide;

1-3 parts of borax;

2-6 parts of bentonite;

6-10 parts of a filler;

5-8 parts of a drier;

1000 portions of water and 1300 portions of water;

the drier consists of sorbitol, sodium polyacrylate and polyvinyl alcohol, wherein the weight ratio of the sorbitol to the sodium polyacrylate to the polyvinyl alcohol is 1 (0.5-1) to 1-2.

By adopting the technical scheme, the bentonite and the drier are added, and the bentonite, the corn starch and the modified tapioca starch are acted together, so that the drying speed of the glue for compounding the corrugated paper is increased. The bentonite and the filler act together to block part of paper fiber pores and reduce the water permeation into corrugated paper fibers, so that the water is effectively volatilized towards the air, and the drying speed is accelerated. The drier adopts sorbitol and some high molecular compounds, and is matched with the corn starch and the modified tapioca starch together, so that the high molecular compounds in a blending system are improved to be modularized, and the combination of hydroxyl, carbonyl and the like of glucose units in the corn starch and the modified tapioca starch with water through hydrogen bonds is reduced; the corn starch and the drier can be grafted with each other for dehydration to form a network structure, thereby accelerating the water volatilization, accelerating the drying speed and improving the bonding strength of the compound adhesive.

In summary, the volatilization speed of water in the use of the glue for compounding corrugated paper is improved by combining bentonite, filler, modified tapioca starch and drier and respectively adopting ways of blocking the pores of paper fibers, adding a high molecular compound and the like.

Preferably, the filler comprises at least one of kaolin, walnut shell flour.

By adopting the technical scheme, the kaolin, the walnut shell powder and the bentonite are matched, so that fine particles are uniformly distributed in fiber pores on the surface of the paper, the water is prevented from being subjected to fiber, and the drying speed of the glue for compounding the corrugated paper is increased. Meanwhile, the filler, the bentonite and the starch can generate high-cohesiveness substances, so that the adhesive strength of the glue for compounding the corrugated paper is effectively enhanced.

Preferably, the modified tapioca starch is prepared by the following steps:

a1, mixing the cassava starch with water, adding the nonionic surfactant after uniformly mixing, and obtaining primary cassava starch after uniformly mixing;

a2, mixing the primary cassava starch and polyacrylamide at the temperature of 75-85 ℃, adding an initiator and a silane coupling agent after uniform mixing, drying and crushing after 1-3h to obtain the modified cassava starch.

By adopting the technical scheme, the nonionic surfactant is added firstly, so that the aggregation of the cassava starch is reduced, the dispersion effect is improved, and the cassava starch is better and uniformly mixed with other raw materials. And then adding polyacrylamide, copolymerizing the primary cassava starch and the polyacrylamide under the action of an initiator and a silane coupling agent, blocking pores on the surface of the paper fiber, and further reducing the combination of hydroxyl groups and other groups in the cassava starch with water through hydrogen bonds, thereby further improving the drying speed of the glue for corrugated paper compounding and shortening the drying time.

Preferably, the weight ratio of the cassava starch, the polyacrylamide and the nonionic surfactant is 1 (0.2-0.5) to (0.01-0.03).

By adopting the technical scheme, the weight ratio of the raw materials in the preparation process of the modified cassava starch is optimized, the raw materials are matched with each other, the obtained modified cassava starch is endowed with a higher drying speed after being added into the glue for compounding the corrugated paper, and meanwhile, the raw materials are prevented from being added more, so that the waste of the raw materials is effectively reduced, and the cost is saved.

Preferably, in the step a1, the nonionic surfactant includes at least one of alkyl glycoside and polysorbate.

By adopting the technical scheme, the alkyl glycoside and the polysorbate are preferably selected, the surface of the cassava starch is effectively modified, and the cassava starch is endowed with better dispersing performance, so that the cassava starch can be effectively and better combined with polyacrylamide, the hydroxyl is hidden, the combination of the hydroxyl and other groups in the cassava starch with water through hydrogen bonds is reduced, the drying speed is further improved, and the drying time is shortened.

Preferably, the raw material of the glue for compounding corrugated paper also comprises 1-3 parts by weight of an accelerant, and the accelerant comprises at least one of eucalyptus powder and boron carbide.

By adopting the technical scheme, the eucalyptus powder in the accelerant contains more potassium chloride, and after the potassium chloride is matched with boron carbide and bentonite, potassium-based bentonite is formed, so that pores on the surface of corrugated paper fibers are further blocked, moisture permeation is reduced, and the purpose of quick drying is achieved; the boron carbide is matched with the eucalyptus powder, the bentonite and the drier to form a glass phase with a compact structure on the surface of the corrugated paper, so that the bonding strength of the glue for compounding the corrugated paper is further enhanced.

Preferably, the accelerant consists of eucalyptus powder and boron carbide in a weight ratio of 1 (1-2).

By adopting the technical scheme, the specific components and the weight ratio in the accelerant are optimized, the drying speed of the glue for corrugated paper compounding is further accelerated, and the bonding strength of the glue for corrugated paper compounding is enhanced.

In a second aspect, the application provides a preparation method of glue for compounding corrugated paper, which adopts the following technical scheme: a preparation method of glue for compounding corrugated paper comprises the following preparation steps:

s1, heating 600 parts by weight of 500-50 ℃ water to 35-50 ℃, adding the corn starch and the modified tapioca starch, mixing uniformly, adding sodium hydroxide, and continuously mixing uniformly; adding the balance of water and borax after 60-80min, and uniformly mixing to obtain a first mixture;

and S2, adding the filler, the drier and the bentonite into the first mixture, and uniformly mixing to obtain the glue for compounding the corrugated paper.

By adopting the technical scheme, firstly, part of water is mixed with starch and sodium hydroxide, part of starch is pasted, and then boric acid is added to enhance the bonding strength of the compound adhesive. And then, the filler, the drier and the bentonite are added, so that the mutual combination of hydrogen bonds of the corn starch and the modified cassava starch with water through the hydrogen bonds is effectively reduced, the water volatilization is accelerated, and the drying speed of the glue for compounding the corrugated paper is further accelerated.

Preferably, in step S2, 1 to 3 parts by weight of an accelerator is added to the first mixture and mixed with the filler, the drier, and the bentonite.

By adopting the technical scheme, the accelerator is added step by step, and the accelerator and the drier and other substances have good matching effect, so that the drying speed is further accelerated, and the bonding strength is improved.

In summary, the present application has the following beneficial effects:

1. in the application, substances such as bentonite and filler are added to effectively block part of fiber pores on the surface of the corrugated paper, so that the moisture is reduced from permeating into the corrugated paper, the moisture is volatilized in the air, and the drying speed is accelerated; and adding a drier, modifying the cassava starch, and reducing the combination of the corn starch, the modified cassava starch and water with hydrogen bonds, so that the volatilization of water is accelerated, and the drying speed is further increased.

2. In the application, kaolin and walnut shell powder are preferably used as fillers and matched with bentonite, so that the water is further reduced from permeating into the fiber pores of the corrugated paper, and the drying speed of the glue for compounding the corrugated paper is increased; in addition, the drying time is further shortened by modifying the cassava starch. At the same time, at least one of eucalyptus powder and boron carbide is added into the glue for compounding the corrugated paper as an accelerant, so that the drying effect is further realized, and the adhesive strength of the glue for compounding the corrugated paper is enhanced.

3. According to the preparation method, the raw materials are added step by step, firstly, the corn starch and the modified tapioca starch are partially gelatinized, then the gelatinized corn starch and the modified tapioca starch are mixed, the better adhesive strength is generated, and then the raw materials such as the filler and the drier are added, so that the drying speed of the glue for corrugated paper compounding is accelerated.

Detailed Description

The present application is described in further detail below.

The components and manufacturers in the examples are shown in Table 1.

TABLE 1 Components and manufacturers

Preparation example

Preparation example 1A modified tapioca starch, comprising the specific components and weights shown in Table 2, comprises the following preparation steps:

a1, mixing and stirring cassava starch and water at a stirring speed of 200r/min, adding a nonionic surfactant fatty alcohol-polyoxyethylene ether after uniformly stirring, mixing and stirring at a stirring speed of 200r/min, and uniformly stirring to obtain primary cassava starch;

a2, mixing and stirring the primary cassava starch and acrylic resin at the temperature of 75 ℃, stirring at the speed of 300r/min, adding an initiator and a silane coupling agent after stirring uniformly, drying and crushing after mixing and stirring uniformly for 3 hours to obtain the modified cassava starch.

Preparation example 2A modified tapioca starch, which is different from the preparation example 1 in that the modified tapioca starch comprises the following specific components and weight as shown in Table 2, and comprises the following preparation steps:

a1, mixing and stirring cassava starch and water at a stirring speed of 200r/min, adding a nonionic surfactant fatty alcohol-polyoxyethylene ether after uniformly stirring, mixing and stirring at a stirring speed of 200r/min, and uniformly stirring to obtain primary cassava starch;

a2, mixing and stirring the primary cassava starch and polyacrylamide at 85 ℃, stirring at the speed of 300r/min, adding an initiator and a silane coupling agent after stirring uniformly, drying and crushing after 1h to obtain the modified cassava starch.

Preparation examples 3 to 4A modified tapioca starch, which is different from preparation example 2 in the weight of each component, and the specific components and weights included are shown in Table 2.

Preparation examples 5 to 6A modified tapioca starch, which is different from preparation example 4 in specific components and weight of a nonionic surfactant, and the specific components and weight included are shown in Table 2.

TABLE 2 specific Components and weights in preparations 1-6

Examples

Example 1A corrugated paper composite adhesive, comprising the specific components and weights shown in Table 3, was prepared by the following steps:

s1, heating the first part of water to 35 ℃, adding the corn starch and the modified cassava starch of the preparation example 1, mixing and stirring at the stirring speed of 300r/min, adding sodium hydroxide, continuously mixing and stirring uniformly; adding the balance of water and borax after 80min, mixing and stirring at the stirring speed of 500r/min, and uniformly stirring to obtain a first mixture;

and S2, adding the filler, the drier and the bentonite into the first mixture, mixing and stirring at the stirring speed of 500r/min, and uniformly stirring to obtain the glue for compounding the corrugated paper.

Example 2 a corrugated paper composite adhesive, different from example 1 in the components and weight, in which the first part of water is heated to 50 ℃ in step S1, 60min later, the rest of water and borax are added and mixed; the specific components and weights included are shown in table 3.

Examples 3-4 a corrugated paper composite gum, different from example 1 in the specific components and weights of the filler, included in the specific components and weights shown in table 3.

Examples 5 to 9A glue for compounding corrugated paper, which is different from example 4 in that the modified tapioca starch of preparation example 1 in example 4 was replaced with the same amount of preparation examples 2 to 6, respectively; examples 5 to 9 correspond to preparation examples 2 to 6, respectively.

Examples 10 to 11 a corrugated paper composite glue, which is different from example 9 in that the accelerator was added in step S2, and the modified tapioca starch of preparation example 6 was still used, and the specific components and weights included are shown in table 3.

Examples 12-13A corrugated paper composite glue, differing from example 11 in the specific components and weights of the accelerator, was still used with the modified tapioca starch of preparation 6, the specific components and weights included being as shown in Table 3.

Examples 14-15 a corrugated paper composite gum, which differs from example 13 in that the modified tapioca starch of preparation 6 was still used, and other components and weights were different, and the specific components and weights included are shown in table 3.

TABLE 3 Components and weights of examples 1-4, examples 10-15

Comparative example

Comparative example 1a glue for corrugated cardboard compounding, which differs from example 1 in that the same amount of polyvinyl alcohol was used instead of sorbitol and sodium polyacrylate.

Comparative example 2 a corrugated paper composite gum differs from example 1 in that the same amount of sorbitol is used instead of polyvinyl alcohol and sodium polyacrylate.

Comparative example 3 a corrugated paper composite gum differs from example 1 in that the same amount of sodium polyacrylate is used instead of polyvinyl alcohol and sorbitol.

Comparative example 4 a glue for corrugated cardboard compounding differs from example 1 in that the same amount of polyvinyl alcohol was used instead of sorbitol.

Comparative example 5 a corrugated paper composite glue differs from example 1 in that the same amount of zinc isooctanoate was used instead of the drier.

Comparative example 6 a glue for corrugated paper compounding, which differs from example 1 in that an equal amount of unmodified tapioca starch was used instead of modified tapioca starch.

Comparative example 7 a glue for corrugated paper compounding, which differs from example 1 in that the drier is replaced by an equal amount of zinc iso-octoate and the modified tapioca starch is replaced by an equal amount of unmodified tapioca starch.

Comparative example 8A glue for corrugated paper compounding, consisting of 100kg of corn starch, 400kg of water, 100kg of acrylic acid and 0.1kg of dodecanethiol, 0.5kg of sodium benzoate, 0,5kg of sodium tetraborate and 5kg of bentonite.

The preparation method comprises the following steps: mixing corn starch and water, adding acrylic acid and dodecyl mercaptan after uniformly mixing, and then heating to 80 ℃ for gelatinization. After pasting, placing the corrugated paper composite glue in a ray radiation field for radiation graft polymerization, then adding sodium benzoate and sodium tetraborate, stirring and dissolving, then adding bentonite, and stirring uniformly to obtain the corrugated paper composite glue.

Detection method

Experiment one: drying speed test

Experimental samples: two pieces of corrugated paper with the same size are respectively bonded by adopting examples 1-15 and comparative examples 1-8 in a longitudinal bonding mode, the corrugated paper bonded by the examples 1-15 is respectively named as experimental samples 1-15, the corrugated paper bonded by the comparative examples 1-8 is respectively named as comparative samples 1-8, and the experimental samples 1-15 and the comparative samples 1-8 are respectively 5.

An experimental instrument: a clock.

The experimental method comprises the following steps: the time for preparing test sample 1 by just bonding two pieces of corrugated paper in each example is recorded as S1; after the compounding glue of each example was dried (i.e., fully cured), the recording time was S2; the drying time is S2-S1.

Taking an experimental sample 1 as an example, 5 pieces of corrugated paper of the embodiment 1 are firstly bonded with the corrugated paper by the glue, and the recording time is S1; after each example 1 had been sufficiently moisture dried, the time was recorded at S2; the drying time of example 1 in 5 experimental samples 1 was calculated, and the average of the 5 drying times was taken as the final drying time of experimental sample 1.

The experimental results are as follows: the results of the drying rate test for the experimental samples 1 to 15 and the comparative samples 1 to 8 are shown in Table 4.

Experiment two: adhesion Strength test

Experimental samples: adopting the examples 1-15 and the comparative examples 1-8 to respectively bond two pieces of corrugated paper with the same size, wherein the size of the corrugated paper is 25mm multiplied by 80 mm; the corrugated papers bonded by the examples 1 to 15 are respectively named as experimental samples 1 to 15, the corrugated papers bonded by the comparative examples 1 to 8 are respectively named as comparative samples 1 to 8, and 5 corrugated papers are respectively named as experimental samples 1 to 15 and comparative samples 1 to 8.

An experimental instrument: a compression strength tester.

The experimental method comprises the following steps: the adhesion strength test experiments were carried out on the experimental samples 1 to 15 and the comparative samples 1 to 8 according to the detection method in the determination of the adhesion strength of corrugated cardboard of the national standard GB/T6548-1998. The values of the adhesive strength were recorded separately and averaged as a result of the adhesive strength. For example, values of adhesive strength were recorded for the adhesion of 5 experimental samples 1 and averaged as a result of the adhesive strength.

The adhesive strengths of the experimental samples 2 to 15 and the comparative samples 1 to 8 were obtained by the above experimental methods, respectively.

The experimental results are as follows: the results of the adhesion strength test of the experimental samples 1 to 15 and the comparative samples 1 to 8 are shown in Table 4.

TABLE 4 results of the experiments of the experimental samples 1 to 15 and the comparative samples 1 to 8

As can be seen from the experimental data in Table 4, the drying time of the experimental samples 1-15 was 37-54min, and the adhesive strength was 816-. The drying time of comparative samples 1 to 8 was 62 to 83min, and the adhesive strength was 691-782N/m. The experimental samples 1-15 have a shorter drying time and a higher adhesive strength than the comparative samples 1-8, indicating that the experimental samples 1-15 have better quick-drying properties and higher adhesive strength.

Comparing the experimental sample 1 and the comparative samples 1 to 5, it can be seen that the drying speed of the glue for corrugated paper compounding is increased and the adhesive strength is enhanced after the drier is composed of sorbitol, sodium polyacrylate and polyvinyl alcohol. Probably because the high molecular compounds, the corn starch and the modified tapioca starch form a blending system after the combination of the substances, and the combination of the hydroxyl groups of glucose units of the corn starch and the modified tapioca starch, sugar agents and other groups with water through hydrogen bonds is reduced, so that the water can be effectively volatilized. Meanwhile, the corn starch and the drier can be grafted and dehydrated to form a net structure, so that the drying speed is increased, and the bonding strength is enhanced. Comparing the experimental sample 1 and the comparative samples 5-7, it can be seen that the corrugated paper composite adhesive with good quick-drying performance and bonding performance can be obtained after the modified cassava starch is simultaneously preferably selected as the drier.

Comparing the experimental sample 1 and the experimental samples 3-4, it can be seen that after at least one of kaolin and walnut shell powder is selected as the filler, the drying speed of the glue for corrugated paper compounding is increased, and the adhesive strength is enhanced, which indicates that the kaolin and walnut kernel powder as the filler can enhance the adhesive strength of the glue for corrugated paper compounding and increase the drying speed.

Comparing the experimental samples 4-7, it can be seen that when the weight ratio of the components is optimized in the process of modifying the tapioca starch, the corrugated paper compound glue with short drying time and high adhesive strength can be obtained; comparing the experimental samples 7-9, it can be seen that, after the alkyl glycoside and the polysorbate are preferably used as the nonionic surfactant, the tapioca starch can be better dispersed, so that the tapioca starch can be better copolymerized with polyacrylamide, and the corrugated paper composite glue with high drying speed and high adhesive strength can be obtained.

Comparing with experimental samples 9-11, it can be seen that the accelerator is potassium-based bentonite formed by mixing eucalyptus powder and boron carbide with bentonite, so as to further block part of pores on the surface of the corrugated paper fiber, reduce water permeation and achieve the purpose of quick drying. Comparing the experimental samples 11 to 13, it can be seen that the weight ratio of the accelerator is preferably selected so that the accelerator can be better mixed with bentonite and a drier, thereby increasing the drying speed of the glue for corrugated paper lamination and enhancing the bonding speed of the glue for corrugated paper lamination.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.