Background technology:
In order to eliminate " white pollution " that the disposable plastic tableware causes to environment, people begin to use in a large number degradable plant fiber type food and drink tool in recent years, and it comprises straw fiber tableware, bagasse tableware, wood pulp cellulose tableware etc.The important parameter of weighing the paper container of food or beverage quality is intensity, water-repellancy and grease proofness, the method that wherein guarantees its water and oil-resistant is to add water and oil repellent agent before paper table ware is shaped and formalizes, the water and oil repellent agent that adds must satisfy conditions such as the easy dispersion of nontoxic, no burn into, after also should considering to make paper table ware to be shaped smooth finish is preferably arranged, cost can not be too high.
The water-resisting agent that is applicable to the paper container of food or beverage industry at present mainly contains emulsified olefin, waterproofing agent of organosilicon, four types of organic fluorine polymer and vinylbenzene-acrylate copolymer emulsions etc.Though emulsified olefin has the better waterproof energy, its more difficult emulsification, the poor stability of emulsion, and only be only applicable to surface treatment, thereby difficult at present the popularization.The waterproof effect of waterproofing agent of organosilicon is fabulous, the erosion of nontoxic nothing, but it costs an arm and a leg, and the film-forming temperature height, the film that forms at fiber surface is easily seen through by air, thereby has influenced the overall quality of paper table ware.The organic fluorine polymer has the anti-oily effect of waterproof preferably, but at present main dependence on import, prices are rather stiff for it, and decomposite objectionable impurities easily when the high temperature more than 200 ℃.The macromolecular water-soluble resin of vinylbenzene-acrylate copolymer emulsion for adopting the conventional emulsion polymerization method to obtain, glossiness height after the film forming, but its water-repellancy is poorer than above-mentioned several prods, thereby large usage quantity, and its latex particle size is big, stability of emulsion is relatively poor, thereby also is in the trial period at present.
Technology contents:
The inventor provides a kind of good water-proof effect through research and exploration, the stability of emulsion height, and easily degraded, cost is low, meets water-proofing agent for paper container of food or beverage and production method thereof that food sanitation requires.
This paper table ware water-resisting agent is the water miscible liquid by the nano level synthetic resins of a kind of quaternized trimer and co-emulsifier, styrene derivatives and (methyl) acrylic ester copolymer.
Quaternized trimer recited above is made up of dimethylaminoethyl acrylate methyl ammonia ethyl ester, vinyl toluene and methyl methacrylate, and the mass content of three kinds of materials in trimer is:
Dimethylaminoethyl acrylate methyl ammonia ethyl ester 10%-40%
Vinyl toluene 45%-75%
Methyl methacrylate 4%-35%
Co-emulsifier recited above can be selected oligomerization non-ionic type co-emulsifier, also can select low molecular weight cationic type co-emulsifier, and the mass content of co-emulsifier accounts for 3%-15% of water-proofing agent for paper container of food or beverage emulsion.Wherein oligomerization non-ionic type co-emulsifier is the reaction product of alkane and lipid acid, for example the reaction product of oxyethane and styracin, stearic acid, oleic acid, Viscotrol C; Cationic as phenmethyl-dodecyl-alkyl dimethyl ammonium chloride etc.Here the molecular formula of nonionic emulsifier can be expressed as follows:
R
1—X—(CH
2—CH
2—0)
n—H
In the formula: X: expression 0, NH or COO
R
1: the senior aliphatic group of 6-30 carbon atoms, cycloaliphatic alkyl, aryl
N: 〉=2 integer
The molecular formula of described positively charged ion co-emulsifier can be expressed as follows:
In the formula:
R
2And R
3Refer to have the senior fatty alkyl or the aryl of 6-20 carbon atoms
R
4And R
5Refer to contain the lower aliphatic alkyl of 1-6 carbon atoms
A halide-ions of y-refer to
The quality of above-mentioned styrene derivatives and (methyl) acrylate mixture is 2-4 times of co-emulsifier total amount.
The production method of water-proofing agent for paper container of food or beverage recited above is as follows:
Produce quaternized trimer intermediate
In reactor, add certain alcoholic solvent, logical nitrogen flooding oxygen, under the effect of azo-initiator (or organic peroxy class initiator), make dimethylaminoethyl acrylate methyl ammonia ethyl ester, vinyl toluene and methyl methacrylate generation copolymerization, temperature of reaction is 60-100 ℃, trimer forms back adding quaternizing agent and makes its cationization, and add acid for adjusting pH value to 2-5, make homogeneous, transparent polymeric surface active agent intermediate.
Quaternizing agent recited above can be tosic acid, butyl chloroacetate or epoxy chloropropane, and described acid is hydrochloric acid or acetic acid.
Described initiator can be in dibenzoyl peroxide, dilauroyl peroxide, and dicumyl peroxide, the special butyl ester of peroxidation phenylformic acid, 2,2'-Azobis(2,4-dimethylvaleronitrile) is selected in the Diisopropyl azodicarboxylate.
Produce water-resisting agent
Deionized water is added in the reactor, add intermediate and co-emulsifier that the first step obtains then, stir, obtain the stable microemulsion liquid system, be warming up to 50-98 ℃, slow drip styrene derivative and (methyl) acrylate mixing monomer, under the initiation of peroxide initiator, reacted 10-20 hours, it is stable to make it to obtain a kind of system, the colloid dispersive, very transparent macromolecule resin water miscible liquid with residual monomer and removal of solvents, can obtain the nm-class water-proofing agent for paper container of food or beverage of median size less than 100nm through underpressure distillation.
The two step synthetic routes that characteristics of the present invention are to adopt solution polymerization and micro-emulsion polymerization to combine, the purpose of solution polymerization is synthetic a kind of by dimethylaminoethyl acrylate methyl ammonia ethyl ester, the quaternized trimer of the chemical homogeneous that vinyl toluene and methyl methacrylate are formed, this quaternized trimer is a kind of special polymeric surface active agent, can with oligomerization non-ionic type co-emulsifier or low molecular weight cationic type co-emulsifier in microvesicle through nucleation, coalescent, it is thermodynamically stable to make the 0/W type after reunion and the thermal treatment, isotropic microemulsion system, and make styrene derivatives and (methyl) acrylate in this microemulsion system, copolymerization take place under the effect of peroxide catalyzed, obtain a kind of stable, the colloid dispersive, very transparent, the average latex particle diameter is the water miscible liquid of the high molecular synthetic resin of 50~100nm, this water miscible liquid is water-proofing agent for paper container of food or beverage, can form one deck waterproof membrane at fiber surface after its film forming, thereby give the paper container of food or beverage favorable waterproof property.
In addition, in the process that forms microemulsion system, the adding of co-emulsifier plays a part very crucial, and it can improve the stability of quaternized trimeric homogeneity and emulsion.
The present invention compares with prior art and like product and has the following advantages:
The quaternized trimer intermediate that employing is made up of dimethylaminoethyl acrylate methyl ammonia ethyl ester, vinyl toluene and methyl methacrylate is as emulsifying agent, because this quaternized trimer is a kind of special polymeric surface active agent, it can be by the transfer reaction of self the grafting reaction (being graft copolymerization) of initiated polymerization thing, make in microemulsion system take place polymeric styrene derivatives and (methyl) acrylate copolymer can grafting on high-molecular weight trimer emulsifying agent, thereby the stability of water-resisting agent emulsion is obviously improved.
The quaternized trimer intermediate that is obtained by solution polymerization can be used with oligomerization non-ionic type co-emulsifier or low molecular weight cationic type co-emulsifier, after special processing, make thermodynamically stable, isotropic microemulsion system, utilize micro-emulsion technology can synthesize a kind of chemical homogeneous, the colloid dispersive, very transparent styrene derivatives and (methyl) acrylate copolymer water miscible liquid, this water miscible liquid system belongs to a kind of thermodynamic stable system, in depositing process, be difficult for to take place coalescent and cause breakdown of emulsion and precipitation, thereby improved the preservation period of water-resisting agent greatly.In addition, because this water-resisting agent latex particle size less than 100nm, can improve the appearance surfaces performance of paper container of food or beverage, its surface smoothness, smoothness and neat and well spaced degree are obviously improved.
Water-resisting agent of the present invention has good film forming properties (film-forming temperature is lower than 100 ℃), formed water-repellent film even compact, thereby have good waterproof effect and an anti-ventilation property, can improve simultaneously the physical strength of paper product to a certain extent, be applicable in the slurry of WATER REPELLENT, hard size paper of paper container of food or beverage or top sizing and make the White Board water repellent agent.
By the component of (methyl) acrylate copolymer that comprises styrene derivatives as food wrapper and cardboard, for many years in the safety of America operation, the paper container of food or beverage that utilizes this products production is also through the detection of relevant hygiene department of China and U.S. FDA, the result all belongs to non-toxic substance, as seen, the present invention meets the requirement of food sanitation safe.
The pH value scope that this product uses is wide, can use under acidity or weak basic condition, especially best results under weakly alkaline (pH value 8.5) condition.
Embodiment:
Synthetic embodiment:
The first step: intermediate synthetic
34 kilograms of methyl alcohol are joined in the 300 liter reactors, start stirrer, feed high-purity nitrogen to drive oxygen, be warming up to 80-120 ℃ then, (wherein dimethylaminoethyl acrylate methyl ammonia ethyl ester is 8-20 kilograms to drip mix monomer I under this temperature, 40-48 kilograms of vinyl toluenes, 5-16 kilograms of methyl methacrylates) and 1-4 kilograms of initiators (BPO), owing to have heat to emit in the reaction process, too concentrated for fear of temperature in the kettle rising suddenly and heat release, to note on the one hand taking necessary forced cooling measure, answer proper extension to drip the time of monomer and initiator on the other hand, notice that simultaneously monomer and initiator will mate dropping, be controlled at about 4-8 hours and drip, restir 2-4 hours adds then and replenishes 0.1-0.6 kilogram of initiation reaction of initiator, continues stirring reaction 2-8 hours.After treating that trimer forms, be cooled to 40-60 ℃ rapidly, in 30 minutes, be added dropwise to quaternizing agent (9 kilograms butyl chloroacetates), continue then to stir 2-6 hours, the hydrochloric acid adjust pH to 2-5 that adds 6.5 kilograms at last reacted 30 minutes, stopped nitrogen, so far, the building-up reactions of intermediate is all finished.
The synthetic embodiment of the second step water-resisting agent
Example 1:
479 kilograms deionized waters are joined in the 1000 liter reactors, (rotating speed is adjustable to start stirrer, be 125-500r/min), logical nitrogen flooding oxygen, be warming up to boiling, be cooled to 80-90 ℃ then, the intermediate that first reaction obtained all is evacuated in the still, the non-ionic type co-emulsifier M that adds 15-20 kilograms simultaneously, stirring velocity is transferred to 500r/min, violent stirring in 5-10 minutes, and after special processings such as thermal treatment, make the microemulsion system of stable uniform, again mixing speed is recalled to 85r/min then, the p-methylstyrene that in still, adds 2-8 kilograms, 2-8 kilograms isobutyl acrylate, reacted 0.5-1 hour, beginning drips mix monomer (each 72 kilograms of p-methylstyrene and isobutyl acrylate) in still, control 2-6 hours and drip off, continue reaction 6-8 hours again, stop nitrogen, and cool the temperature to 50~55 ℃, close the condensing reflux valve, carry out underpressure distillation to remove residual monomer and solvent, distillation time is about 1~2 hour, add deionized water at last to replenish the component that is distilled away, can obtain particle diameter less than 100nm's, stable, light yellow transparent water-resisting agent.
Example 2:
492 kilograms deionized waters are joined in the 1000 liter reactors, (rotating speed is adjustable to start stirrer, be 125-500r/min), logical nitrogen flooding oxygen, be warming up to boiling, be cooled to 70-80 ℃ then, the intermediate that first reaction obtained all is evacuated in the still, the cationic co-emulsifier N+ and the F+ that respectively add simultaneously 6-9 kilograms, stirring velocity is transferred to 500r/min, violent stirring in 5-10 minutes, and after special processings such as thermal treatment, make the microemulsion system of stable uniform, again mixing speed is recalled to 85r/min then, the o-methyl styrene and the vinylformic acid-2-ethylhexyl that in still, respectively add 6-8 kilograms, reacted 0.5-1 hour, in still, drip mix monomer (wherein o-methyl styrene and vinylformic acid-2-ethylhexyl each 72 kilograms) and with 75 kilograms of water-reducible 5-9 kilograms hydrogen peroxide initiation reactions, dripped off in 2-4 hours, continue reaction 4-6 hours again, add with 7 kilograms of water-reducible 1.5 kilograms of hydrogen peroxide, continue reaction 1-2 hours, stop nitrogen, and cool the temperature to 50~55 ℃, close the condensing reflux valve, carry out underpressure distillation to remove residual monomer and solvent, distillation time is about 1~2 hour, adds deionized water at last to replenish the component that is distilled away, can obtain particle diameter less than 100nm's, stable, light yellow transparent water-resisting agent.
Application Example:
Get 20 kilograms bleaching bagasse pulp, the concentration of size degradation, making beating and furnishing 1%, the beating degree of paper pulp is 25 OSR, the water-resisting agent that adds 800ml (be oven dry stock 4%), the F-321 oil-proofing agent of 400ml (be oven dry stock 2%) PPE-L toughener and 140ml (be oven dry stock 0.7%), obtain the paper table ware sample behind shaping and setting treatment, after testing, the main performance index of this paper table ware product is as follows:
Water tolerance: 95 ℃ hot water 2 hours is non-leakage;
Oil-proofness: 150 ± 5 ℃ deep fat 2 hours is non-leakage;
Load-bearing capacity: dimensional change≤5% (3kg);
Degradation property: deposit high-fall separating after 50 days naturally;
Whiteness: 〉=78% (IS0)
Toxicity check: meet the food hygienic standard requirement
In a word, the every performance index of the sample of being produced all reach the Ministry of Railways about " railway mess-tin the supply of material general technical specifications " (TB/T2611-94) and the requirement of GB18006.1-1999.