Technical background
Along with the increase of logistics capacity, the demand of packing board/case is also more and more.Since packing board/case deposit and transportation in, all can be subjected to influences such as external force, atmospheric humidity, so also higher to the requirement of aspects such as the adhesive strength of packing board/case, water resistance.Along with the raising of people's environmental consciousness, also more and more higher simultaneously to the feature of environmental protection requirement of wraparound carton, especially, more to guarantee nontoxic to the food and medicine packing.Tradition starch bonding agent is to make with raw materials such as water, starch, boraxs substantially, corrugated board/the case that uses this type of adhesive bonds is poor water resistance not only, and bonding strength, hardness and deflection aspect are also undesirable, easily cause carton moisture absorption deliquescing, the edge phenomenons such as perk, distortion of coming unstuck.Promptly can come unglued voluntarily, separate in 5~10 minutes with the bonding corrugated board of starch bonding agent/case immersion, not reach water-fast requirement.Be to solve the resistance to water problem, can in gelatinized corn starch, add melamine resin, Lauxite, phenolic resins and make the water resistant starch adhesive, to improve the adhesive strength and the water resistance of corrugated fibre box.As Chinese patent literature CN1597822A disclosed " corrugated board/case water resistant fortifier and preparation technology thereof ", the raw material of this reinforcing agent and proportioning are 80~100 parts of formaldehyde; 26~38 parts of urea; 0.8~1.2 parts of hexamethylenetetramines; 2.2~4 parts of melamines and 0.1~0.4 part of acrylamide, solid content also has close effect 55~60%.But this type of resin-formaldehyde content height can cause environmental pollution, especially during packaged food, causes the pollution to food easily, and it is healthy to influence people, and simultaneously, this resinoid storage life is very short.
Summary of the invention
Technical problem to be solved by this invention is, do not use formaldehyde, can improve resistance to water, humidity resistance and the high-intensity adhesive property of water resistant fortifier again.
Corrugated paper plate water resistant reinforcing agent of the present invention, it is characterized in that being made up of following raw materials by weight percent: glyoxal is 10~30% (being preferably 5~25%), urea is 5~20% (being preferably 10~15%), melamine is 0.3~2% (being preferably 0.5~1%), crosslinking agent is that 0.1~1% (being preferably 0.3~0.7%) polyacrylamide is 1~10% (being preferably 4~8%), and all the other are water; Solid content is 10~35% (being preferably 20~30%); Described crosslinking agent is γ-glycidyl ether oxygen propyl trimethoxy silicane, one or more composite mixture in γ-methacryloxypropyl trimethoxy silane.
Polyacrylamide wherein is any cationic-type polyacrylamide that prior art is used.
The preparation technology of corrugated paper plate water resistant reinforcing agent of the present invention, it is characterized in that raw material is through metering, with glyoxal, urea, melamine and crosslinking agent add in the reactor, add hydrochloric acid solution and transfer pH value to 2~3, logical steam fully heats, insulation, cool, regulate pH value to 6~7 with sodium hydroxide solution, add polyacrylamide and water, obtain product after the cooling.
The application of corrugated paper plate water resistant reinforcing agent of the present invention in making corrugated board is characterized in that the corrugated paper plate water resistant reinforcing agent that adds starch dry weight 4~6% in gelatinized corn starch forms the starch bonding agent for applying.
When corrugated board water resistant fortifier of the present invention mixes with the starch bonding agent, when the moment of bonding agent gelatinization, hydroxyl on functional group on the reinforcing agent macromolecular chain and starch and the paper fiber reacts, make whole system form the complex three-dimensional network structure, not only make bonding agent have superior water-fast, humidity resistance, and improved adhesive strength, hardness and the deflection of corrugated board/case.Through test, add the bonding corrugated board of formaldehydeless water resistant fortifier of the present invention, in water, soak after 48 hours and do not come unglued, again with still bonding firm behind the corrugated board nature airing.Owing to formaldehydeless water resistant fortifier of the present invention has the excellent water tolerance and the feature of environmental protection, the production of suitable various corrugated fibre boxs can be used for using relatively rigorous environment, as the packing of the article that refrigerate, the commodity that need transport by sea and easily get damp.
The specific embodiment
Below by embodiment, technical scheme of the present invention is described in further detail.
The basic preparation technology of embodiment is, raw material is through metering, with glyoxal, urea, melamine adds in the reactor, opens stirring, add 10% hydrochloric acid solution and transfer pH value to 2~3, logical steam heated to 50~80 ℃, be incubated 50~120 minutes, cool, regulate pH value to 6~7 with sodium hydroxide solution to 50~80 ℃, add polyacrylamide, crosslinking agent and water, obtain product after the cooling.
General application process: mix by starch, sheet alkali, the warm water of prior art amount ratio, stir, obtain gelatinized corn starch, add reinforcing agent of the present invention, borax then, obtain the water resistant starch bonding agent with metering.Be transported in the paste groove of production line again, apply on the stupefied peak of corrugated paper by upper paste roller, heat up, applying is finished in gelatinization.
Embodiment 1
With 20 parts of (weight) glyoxals, 10 parts of (weight) urea, 1 part of (weight) melamine adds in the reactor, open stirring, adding 10% hydrochloric acid solution accent pH value is 2~3, logical steam heated to 55 ℃, be incubated 120 minutes, cool to 50 ℃, regulate pH value to 6~7 with 10% sodium hydroxide solution, add 5 parts of polyacrylamides (Hangzhouproization is broadcast the PA-07 that mill papermaking chemical product Co., Ltd produces), (γ-methacryloxypropyl trimethoxy silane+γ-glycidyl ether oxygen propyl trimethoxy silicane (both weight ratios are 1: 1) adds water to 100 weight portions to 0.5% crosslinking agent, make its solid content reach 30~35%, obtain corrugated paper plate water resistant reinforcing agent product after the cooling, product shelf life is more than 6 months.
Effect: in gelatinized corn starch, add the product of starch dry weight 4%, form the water resistant starch bonding agent.This bonding agent has good first bonding force, and with the cardboard that this bonding agent posts, resistance to water is good, does not throw off (five layers) in 48 hours under water, and triplex board was not thrown off in 60 hours under water.
Embodiment 2
With 25 parts of (weight) glyoxals, 8 parts of (weight) urea, 0.5 part of melamine add in the reactor, open stirring, add 10% hydrochloric acid solution accent pH value to 2~3, logical steam heated to 80 ℃, be incubated 50 minutes, be incubated 90 minutes, cool to 80 ℃, regulate pH value to 6~7, add 7 parts of (weight) polyacrylamides with 10% sodium hydroxide solution; 0.4% crosslinking agent (γ-glycidyl ether oxygen propyl trimethoxy silicane); Add suitable quantity of water, make its solid content reach 30~35% water, obtain product after the cooling, product shelf life is more than 6 months.
Effect: in gelatinized corn starch, add the product of starch dry weight 5%, form the water resistant starch bonding agent.This bonding agent has good first bonding force, and with the cardboard that this bonding agent posts, resistance to water is good, does not throw off (five layers) in 48 hours under water, and triplex board was not thrown off in 60 hours under water.
Embodiment 3
With 20 parts of (weight) glyoxals, 10 parts of (weight) urea, 1.5 parts of melamines add in the reactor, open stirring, add 10% hydrochloric acid solution accent pH value to 2~3, logical steam heated to 80 ℃, be incubated 50 minutes, be incubated 90 minutes, cool to 80 ℃, regulate pH value to 6~7, add 7 parts of (weight) polyacrylamides with 10% sodium hydroxide solution; 0.4% crosslinking agent (γ-methacryloxypropyl trimethoxy silane); Add suitable quantity of water, make its solid content reach 30~35% water, obtain product after the cooling, product shelf life is more than 6 months.
Effect: in gelatinized corn starch, add the product of starch dry weight 4%, form the water resistant starch bonding agent.This bonding agent has good first bonding force, and with the cardboard that this bonding agent posts, resistance to water is good, does not throw off (five layers) in 24 hours under water, and triplex board was not thrown off in 48 hours under water.