CN86104040A - Method for manufacturing polyvinyl alcohol film by blow moulding with biaxially oriented stretching under mormal temp - Google Patents

Abstract

Blow moulding with biaxially oriented stretching under mormal temp is made polyvinyl alcohol (being called for short PVA) film process, with the polymerization degree 500～2200 alcoholysis degrees 97～99.99%PVA, make resin contain wet 40～55%, contain a small amount of nontoxic glyceryl ester, silicone oil, glycerine, melt extrude filtration, deaeration by forcing machine, blowing bubble pipe, twice two-way stretch under the normal temperature, dryness finalization, thermal treatment under the tension force.8～30 microns of product thicknesses, tensile strength 1000～3800 kilograms per centimeter ², extension at break 200～30%, transmittance be more than 90%, oxygen permeating amount

Description

Method for manufacturing polyvinyl alcohol film by blow moulding with biaxially oriented stretching under mormal temp

The present invention is that the approaching polymer polyvinyl alcohol of fusing point and decomposition point is processed into the plastics film method.

The method that the approaching polymer polyvinyl alcohol (hereinafter to be referred as PVA) of existing fusing point and decomposition point is made film has hydrostomia method, film casting method, blow moulding.Hydrostomia method strength of solution is low, power consumption is high, and production efficiency is low; Film casting method equipment is huge, power consumption is high; It is little that blow moulding is made PVA membrane equipment expense, it is low to consume energy, the clear 49-33595 method of Japanese Patent makes PVA resin and water auxiliary agent melt pelletization earlier, adjust moisture content again, add fusion in the forcing machine, be pressed into deaeration in the deaerator with toothed gear pump through pipeline, send into the circular knitting machine head with the toothed gear pump metering through pipeline again and be blow molded into the bubble pipe, give the inside and outside blowing cooling of bubble pipe simultaneously, the clear 50-9820 method of also available Japanese Patent is given in the bubble pipe and is sent warm air drying outside, for preventing adhesion, dusting in the bubble pipe or add earlier the inorganic material powders way in resin with the practical new clear 55-26094 mode of case of Japan solves.The shortcoming of these methods is many granulating working procedure, increases energy consumption and operating performance, no fine filtering device, and impurity and lump easily make the bubble tracheal rupture in the resin, also influence quality product; Equipment used is respectively for operating unit is tediously long mixed and disorderly with the pipeline connection one by one; Prevent the disadvantage that way has powder to fly upward or film clarity descends of adhesion.Therefore the gained film thickness is big, and poor transparency, tensile strength are not high yet.Be to reduce film thickness, with the clear 55-37408 method of Japanese Patent to the heating of bubble pipe, carry out two-way stretch splitting winding after, the thermal treatment of going again gets product, though film thickness has decline like this, quality has raising.But this bubble pipe heating two-way stretch mode is actually dry, stretches, typing carries out simultaneously, and molecular chain is difficult to slip like this, and degree of orientation is poor; So gained film clarity and the not high characteristic of failing to have given play to the PVA resin of intensity, and film increases through heating power consumption repeatedly for three times in whole process of production.

The objective of the invention is to remove existing production method shortcoming, promptly at first change the present situation of ignoring the molten mass quality in the processing, make molten mass secondary filter and deaeration, lose one, make film when containing volume moisture content to thinking the prejudice that under heating, can carry out two-way stretch.When just molecular chain is easy to slide orientation at normal temperatures, the bubble pipe is carried out twice two-way stretch, can make the existing production method of strength ratio like this and exceed PVA film 1～3 times, excellent property, also have operation to simplify the energy saving characteristics.

The present invention at first makes the good swelling of PVA resin, control water capacity 40～55%, for preventing that material from adhering to mouthful mould and inter-adhesive nontoxic glyceride type, the silicone oil etc. of adding of bubble pipe internal surface are made release agent, the disadvantage that no powder flies upward, film clarity descends, the resin that swelling is good directly adds fusion in the forcing machine, no longer granulation, to prevent to pollute and save the energy, melt is with the toothed gear pump metering of boosting, candle-shaped filter through 120～250 order filtering nets are housed filters, blowing after deaeration is difficult for breaking and quality product to guarantee the bubble pipe.Add forcing machine through fusion from the good resin of swelling, metering is boosted, filtration, deaeration, thermosistor are adjusted temperature and entered the circular knitting machine head and be blow molded into six processes of bubble pipe, equipment used respectively is parts one by one, becomes an equipment that comprises the downward blowing head of band of forcing machine.Compact agile, not tediously long mixed and disorderly.The present invention one instead thinks in the past and will can steep the prejudice of managing two-way stretch under heating, except that be blow molded into the two-way stretch of when pipe bubble at head, under normal temperature (10 ℃～35 ℃) in succession twice pair the bubble pipe carry out two-way stretch, comprise that so the total two-way stretch multiple when the bubble pipe forms can arrive 7-8 doubly by height, molecular chain orientation degree height, film is transparent good, and the tensile strength height, unit elongation is low, film thickness is little.For preventing disorientation, bubble pipe after stretching dryness finalization under biaxial tension, during dryness finalization, the dry epimere bubble of perpendicular road hypomere waste heat pipe, there is not sharply heating, film breaks or the very big shortcoming of surfaces externally and internally degree of drying difference, reasonable utilization of energy: dryness finalization is cut the back without rolling, enter thermal treatment in the heat-treating machine at once, operation is simplified than existing production method.

The PVA membrane process is made in the present invention and existing blowing relatively following characteristics: 1. the not high no longer granulation again of temperature when the saving energy is embodied in resin swelling, normal temperature blow molding; Twice two-way stretch under the normal temperature; Heat energy utilization is reasonable during dryness finalization.2. total two-way stretch multiple is big, and the PVA film strength that makes makes 2-7 times of PVA film for existing blow moulding.3. boost from extruding, measuring, filtration, deaeration, refining temperature, carry out to being blow molded in the bubble Guan Zaiyi platform equipment, for existing blow moulding does not possess.4. except that mediating swelling, whole production is a successive.5. the fine filtering operation is arranged.

Detailed process of the present invention is the PVA resin with the alcoholysis degree 97～99.99% of the polymerization degree 500～2200, wash or do not wash, be added on and mediate in the still, add a certain amount of distilled water or soft water again, heat up gradually in being no more than 60 ℃ of temperature, make the abundant swelling of resin, and add 0.1～0.3% nontoxic release agent of amount of resin, as laurostearic acid glyceryl ester, palmitic acid glyceryl ester, 18 triglyceride and 0.1～0.3% silicone oil, as dimethyl silicone oil, hydroxy silicon oil, polymethylphenyl siloxane fluid, also add 0.1～0.6% glycerine and make wetting agent, resin contains wet 40～55% when mediating end, the surface does not have free moisture content, afterwards, resin added in the forcing machine in 70～140 ℃ of temperature ranges, melt extrude, through the toothed gear pump metering of boosting, filtration area is that the candle-shaped filter that 120～250 order filtering nets are housed of 5～20 times of extruder barrel sectional areas filters, the deaerator deaeration, below all be incubated 100～140 ℃, enter again and adjust temperature in the thermosistor of static mixing element and be 100～120 ℃ and enter the garden head, be blow molded into the bubble pipe downwards, keep two-way stretch than 1: 1.5～3.0, the bubble pipe feeds pressurized air again and keeps two-way stretch than 1: 1.2～2.5 behind first pinch roll, the bubble pipe feeds pressurized air and keeps two-way stretch than 1: 1.1～2.0 behind second pinch roll, behind second pinch roll, feed pressurized air and make two-way stretch than keeping 1: 0.8～1.0 to enter the perpendicular road of dryness finalization, long 6～8 meters of perpendicular road, the hypomere heating is no more than 120 ℃, the bubble pipe is when going out to erect the road moisture 10～16%, through being divided into two width of cloth behind winder first pinch roll, behind winder second pinch roll, enter respectively in the double width heat-treating machine, thermal treatment 15～60 seconds, 180～90 ℃ of treatment temps, control film water capacity 5～7%.The total two-way stretch 4.5 of gained PVA film～7.0 o'clock, tensile strength 1000～3800 kilograms per centimeter ², extension at break 200～30%, 8～30 microns of thickness, transmittance be more than 90%, oxygen permeating amount 0.3～6.0 (centimetre ³)/(rice ³It air pressure 24 hours) (20 ℃, the following mensuration of 0～92%RH).The nontoxic odorless, tasteless of gained PVA film, transparency is good, resistance oxygen is good, intensity is high, should make used for packing foods laminated film resistance oxygen base material, packing is wanted the grease proofing product that oozes out product, senior textiles, sublimability is arranged, easy deterioration by oxidation product, packing fruit vegetables, food also can be worked as glassine paper and be used.

Figure of description is a process flow diagram of the present invention.

Example of the present invention: the polymerization degree 1700 ± 50 alcoholysis degree 99.98%PVA resins are put in to mediate adds an amount of moisture content stirring intensification in the still (1); naturally cooling after being raised to 50 ℃ in 30 minutes; treat that swelling well adds 0.1～0.3% 18 triglyceride of amount of resin; 0.2～0.3% dimethyl silicone oil; 0.2% glycerine; to not having free moisture content fashionable dress in bucket (2); resin contains wet 45～47%; resin in (2) is added φ 45mm forcing machine (3) maintenance to melt extrude for 80～130 ℃; toothed gear pump (4) metering of boosting; 200 order filtering net filtration areas are that the candle-shaped filter (5) of 10 times of extruder barrel sectional areas filters; deaerator (6) deaeration; 120～130 ℃ of these insulation of equipments; thermosistor (7) attemperation that material advances to be equipped with static mixing element is 100～110 ℃, and to go into head (8) temperature be 110～80 ℃; 0.6～0.7 millimeter in mouth modular ring crack; send pressurized air to be blow molded into the bubble pipe by head; vane (9) air-supply cooling; mouth mould two-way stretch ratio: laterally inflation is 2～2.5 times; 1.8～2.0 times of longitudinal stretchings; (10～35 ℃) carry out i.e. horizontal 1.8～2.0 times of the inflations behind herringbone nip rolls (10) first pinch rolls (11) of twice bubble pipe two-way stretch at normal temperatures; 1.5～1.8 times of longitudinal stretchings; go out 1.15～1.5 times of the horizontal inflations in second pinch roll (12) back; 1.1～1.3 times of longitudinal stretchings; dryness finalization is for going out 0.8～0.85 times of the horizontal inflation of the 3rd pinch roll (13) under the tension force; 0.9～1.0 times of longitudinal stretching; dryness finalization erects 100～120 ℃ of road (14) hypomere heating; go out to erect the road film and contain wet 12～14%; the bubble pipe is divided into two width of cloth through herringbone nip rolls (15) winder first pinch roll (16) carving knife (17); go out winder second pinch roll (18) and directly entered in the heat-treating machine (19) thermal treatment respectively 20 seconds without rolling, 90～110 ℃ of thermal treatment temps get product through guide roller (20) nip rolls (21) rolling.As total two-way stretch is 4.5～5.5 times of then product fabric width degree 500mm, 22 microns of thickness, and transparency 91.3%, tensile strength are laterally greater than 2000 kilograms per centimeter ², longitudinal strength is greater than 1800 kilograms per centimeter ², extension at break is less than 150%.

Than keeping 6.0～7.0, then product fabric width degree is 600mm, 1.6 microns of film thicknesses, tensile strength 2500～3800 kilograms per centimeter as total two-way stretch ², transparency 91.4% extension at break is less than 50%.

Claims (5)

1. Method for manufacturing polyvinyl alcohol film by blow moulding with biaxially oriented stretching under mormal temp is that the approaching polyvinyl alcohol of fusing point and decomposition point (being called for short PVA) resin is processed into the plastics film method with blow molding process.

   1, polyvinyl alcohol resin, water, swelling adding assistant, forcing machine dissolves, the toothed gear pump input filter filters, the deaerator deaeration, and the two-way stretch of head blowing film forming bubble pipe, dryness finalization are handled the PVA (PVOH) FILM method of making without the rolling direct heat, it is characterized in that water swelling PVA resin and glycerol adding ester and silicone oil makes release agent, bubble pipe twice two-way stretch in succession down of secondary filter melt before the no longer granulation, deaeration, normal temperature, dryness finalization under the tension force directly enters thermal treatment.
2. 2, manufacturing PVA (PVOH) FILM method as claimed in claim 1, it is characterized in that added glyceryl ester is 12,16,18 triglyceride, use with more than any one or two kinds of, consumption is 0.1～0.3% of an amount of resin, the silicone oil that adds be hydroxyl, phenmethyl, dimethyl silicone oil any or use with more than two kinds, consumption is 0.1～0.3% of an amount of resin.
3. 3, manufacturing PVA (PVOH) FILM method as claimed in claim 2 is characterized in that secondary filter, and molten mass is that the filtration area that 120～250 order filtering nets are housed is 5～20 times a candle-shaped filter of forcing machine machine letter sectional area.
4. 4, manufacturing PVA (PVOH) FILM method as claimed in claim 3 is characterized in that at normal temperatures (10 °～35 ℃) carry out twice two-way stretch to the bubble pipe in succession, and each time two-way stretch ratio is 1: 1.1～1: 3.0.
5. The longitudinal stretching ratio was 0.8～1.0 when 5, manufacturing PVA (PVOH) FILM method as claimed in claim 4 is characterized in that bubble pipe dryness finalization, divided to be cut to two width of cloth, directly entered thermal treatment without rolling.

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