CN1326753C

CN1326753C - Self-sealing plastic bag and production method thereof

Info

Publication number: CN1326753C
Application number: CNB2003101132989A
Authority: CN
Inventors: 吴锦生
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-11-14
Filing date: 2003-11-14
Publication date: 2007-07-18
Anticipated expiration: 2023-11-14
Also published as: CN1544296A

Abstract

The present invention provides a self-sealing bag made from polypropylene material. The self-sealing structure of the plastic bag is composed of a female buckle and a subbuckle, wherein the cross section of the female buckle is in a semielliptical ring shape, and both ends of the female buckle are provided with incurvate claw hooks; the cross section of the subbuckle is in the shape of an arrowhead whose both wings are unsymmetrical. The present invention also provides a method for manufacturing the polypropylene self-sealing bag, which comprises the procedure that a formed thin film piece of the polypropylene bag is immediately immersed into water to chill at 20 to 30DEGC after the formed thin film piece leaves a die opening. The intensity, the transparency, the high temperature property, the heat sealing property and the printable property of the polypropylene self-sealing bag of the present invention are superior to those of a polyethylene plastic bag. The self-sealing structure ensures that the polypropylene self-sealing bag can be freely opened and closed.

Description

Self-styled plastic bag

Technical field:

The present invention relates to self-styled Polypropylene Bag, and relate to the production method of this valve bag.

Technical background:

Self-styled plastic bag is a kind of by people's use package packing supplies for many years, and it is widely used in packing medicine, food and other tiny loose packed article.Described self-styled plastic bag is realized self-styled function with double buckle; The symmetrical respectively inboard that also relatively is arranged on plastic bag of son button and box, and the equal in length of son button and box, geomery is complementary.The son button is that a cross section is the sagittate straight plastic strip of symmetry, and box is that a cross section is semicircle shape, and there is the straight plastic strip of aduncate claw hook at the two ends of semicircle.After a little firmly son being withheld box, two wings at the arrow shaped position of son button just are stuck on two claw hooks of box, thereby make the sealing of plastics sack; When a little firmly pullling the plastic bag mouth, just sagittate two wings of child button and corresponding two claw hooks of box can be thrown off, thereby the plastics sack is opened, so that take out or the article of packing into.The plastic bag of this structure is made with polyethylene usually, poly major defect is that poor transparency, high-temperature behavior are poor, intensity difference, heat sealability difference and impressionability difference etc., so people are seeking a kind of performance better material always and substitute the self-styled plastic bag of polyethylene production.

It should be desirable equivalent material that diaphaneity, high-temperature behavior, mechanical strength, heat sealability and impressionability can all be better than poly polypropylene material, but following problem occurred with the valve bag that polypropylene is made:

1. the son button is difficult to insert box, and it is self-styled that sack is difficult to;

2. even firmly reluctantly the child button is inserted box, but be difficult to make the two separation, tear the sack of also not opening sometimes even with plastic bag.

The enclosuring structure that the analysis found that existing Polythene Bag is not suitable for polypropylene material.

Be white in color and opaque through the polypropylene valve bag of blow moulding machine moulding in addition, and because of the embrittlement lacking toughness, therefore, the expectation of present technique field provides:

1. self-styled plastic bag made from polypropylene material;

A sack closure, open polypropylene plastics pocket freely;

3. the production method of the self-styled plastic bag of above-mentioned polypropylene.

Summary of the invention:

The invention provides a kind of self-styled plastic bag, it is characterized in that described self-styled plastic bag makes with polypropylene material;

The sack inboard of described self-styled plastic bag is provided with symmetrically and relatively by child and buckles and box constitutes from seal structure; The cross-sectional plane of described son button is asymmetric arrow-shaped; Described box cross-sectional plane is the semiellipse annular, and its two ends have the claw hook that extends and bend inwards with width ground such as described semiellipse rings downwards; The shape of described son button cross-sectional plane and size are complementary with the shape and the size of box cross-sectional plane.

The ratio of minor axis and major axis of outer rim ellipse of semiellipse ring that constitutes the box cross-sectional plane of described self-styled plastic bag is (7.6～8.6): (10.7～11.25); The ratio that constitutes distance and major axis between the inside and outside ellipse of described semiellipse ring is (0.85～0.95): (10.7～11.25); The distance of the interior end points of one of described claw hook and described semiellipse ring line of centers is (3.5～4) with the ratio of described major axis: (10.7～11.25), the end face of this claw hook are a plane vertical with described inner edge.The end face of described another claw hook also is the plane, and this plane and described major axis are 45, and its point is circular-arc, and its radius is (0.3～0.4) with the ratio of described major axis: (10.7～11.25); The common tangent line of the outer rim of described two claw hooks is parallel with described major axis.

Described son button cross-sectional plane is an asymmetric arrow shaped, and it is positioned at its both sides by straight arrow shaft partial sum and the asymmetric wing of two of being attached thereto portion constitutes; The width of described arrow shaft part is (0.8～1.2) with the ratio of described major axis: (10.7～11.25), and its length is (4.9～5.2) with the ratio of described major axis: (1 0.7～11.2 5); The inner edge of a described wing portion and arrow shaft portion line of centers are 42 °～43 ° angle, the outer rim of this wing portion and this line of centers are 39 °～41 ° angles, described inner edge top with draw from arrow, the distance of the line parallel with major axis is (2.05～2.25) with the ratio of described major axis: (10.7～11.25), the top of this wing are a plane vertical with inner edge; The inner edge of described another wing portion and arrow shaft portion line of centers are 49 °～50 ° angle, its outer rim and this line of centers are 30 °～32 ° angle, and this wing portion end points is (1.8～2.0) with the ratio that draws from the distance of the parallel lines that is parallel to described major axis of arrow end and described major axis: (10.7～11.2 5).

When a little firmly pushing the child button in the box, two wing portions of son button are out of shape because of stressed, thereby be inserted in the box, described then two wings restore to the original state in the space of the semiellipse ring-type of box and launch and hook the claw hook of two bendings of box respectively, thereby two sidewall structures of this plastic bag are lumped together; When needs are opened plastic bag, a little firmly the two side of plastic bag is pullled to reversing sense, two wing stress deformations of this moment son button and from box, deviating from, thus the plastics sack is opened.

The self-styled plastic bag of polypropylene of the present invention can be made with the extruder and the blow molding process of routine, but when the polypropylene plastics pocket diaphragm of making leaves die orifice, and it is immersed in 20～30 ℃ the normal-temperature water 1～2 second immediately to make it chilling.This chilling is handled the intensity and the diaphaneity that can improve plastic bag.

The self-styled plastic bag of polypropylene of the present invention is owing to selected better material, the structure and the shape of the child button and the box of valve bag have been improved, compare with traditional polyethylene valve bag, the self-styled plastic bag of polypropylene of the present invention has diaphaneity height, intensity height, impressionability is good, heat sealability is good, be easy to open and the osed top advantage.In addition, owing in the process of preparation polypropylene valve bag of the present invention, adopted above-mentioned water-cooled step, thus further guaranteed the diaphaneity and the toughness of described polypropylene plastics pocket.

Specifically describe the present invention with reference to the accompanying drawings.

Description of drawings:

Fig. 1 is the drawing in side sectional elevation of the self-styled plastic bag sack of polypropylene box.

Fig. 2 is the drawing in side sectional elevation that self-styled plastic bag sack of polypropylene is buckled.

Referring to Fig. 1, similar to the box of known polyethylene valve bag, the box 1 of polypropylene valve bag of the present invention is also for moulding a straight projection parallel with the sack edge at sack 8 inboard places, its cross-sectional plane is the ring that two ends have the semiellipse shape of extension 2 and 3, the outer long axis of ellipse of this ring is 10.7mm, its minor axis is 7.4mm, and the width of this annulus is 0.9mm; A described extension is an inflexed claw hook 2, and its end face is a plane, it and described major axis angle at 45, and its point is formed the arc that radius is 0.3mm.Another extension is an inflexed claw hook 3, its end face is a plane, the interior end points of claw hook 3 and the distance of described elliptical center line are 3.75mm, referring to Fig. 2, son button 4 is for moulding relative with box and parallel with a sack straight projection at another sack 9 inboard places of polypropylene valve bag, its cross-sectional plane is an asymmetric arrow-shaped, and its length is 4.9mm; Described arrow-shaped portion is made of arrow shaft portion 5, two wings 6 and 7, and the width of arrow shaft portion 5 is 1.0mm, and the inner edge of wing portion 6 becomes 42 ° of 30 ' angles with the arrow shaft line of centers, and its outer rim becomes 40 ° of angles with this line of centers; The interior end points of wing portion 6 is 2.15mm with the distance of drawing between the line parallel with described major axis of arrow end, and the top of wing 6 is a plane vertical with its inner rim; The outer rim of wing portion 7 becomes 30 ° of angles with the arrow shaft line of centers, its inner rim becomes 49 ° of angles with this line of centers, its end points with draw from tip, the distance that is parallel between the line of described major axis is 1.8mm; Described son button and box lay respectively at two bag wall inboards of the plastic bag of moulding accordingly, they are degree apart from the distance of sack upper limb so that strike out and seal plastic bag with the hand, and the bending and the intersection of box and son button can have the natural circular arc that produces because of Mould Machining.In the time of in exerting oneself a little with the semiellipse annular groove of child button 4 insertion boxes 1, two wing portions 6 of son button and 7 insert in the box 1 because of stress deformation, in the recess space of described semiellipse shape, restore to the original state then and after launching, box claw hook 3 and 2 are hooked respectively in described wing portion 6 and 7, thereby sack is sealed; When a little firmly pullling plastic bag two walls, two aliform portions 6 of son button and 7 claw hook 3 and 2 disengagements because of stress deformation and box, thus this plastics valve bag is opened.

The conventional plasticator of polypropylene valve bag of the present invention, blowing is made.After the polypropylene granules of fusion is extruded moulding, it was immersed in 25 ℃ the circulating water 1～2 second immediately, to improve its diaphaneity and toughness.The diaphaneity that above-mentioned polypropylene plastics pocket from seal structure is arranged, high-temperature behavior, intensity, heat sealability and impressionability all are better than conventional polyethylene valve bag.

Claims

1. plastics valve bag, it is made of polypropylene, its from seal structure by cross-sectional plane be the semiellipse ring-type and to have the box of the claw hook that extends with width ground such as described semiellipse rings and bend inwards and cross-sectional plane downwards be that the asymmetric sagittate son of two wings is buckled and constituted at its two ends, and the shape size of described box and son button is complementary, and the ratio of minor axis and major axis of outer rim ellipse of semiellipse ring that it is characterized in that constituting the box cross-sectional plane of described self-styled plastic bag is (7.6～8.6): (10.7～11.25); The ratio that constitutes distance and major axis between the inside and outside ellipse of described semiellipse ring is (0.85～0.95): (10.7～11.25); The distance of the interior end points of one of described claw hook and described semiellipse ring line of centers is (3.5～4) with the ratio of described major axis: (10.7～11.25), the end face of this claw hook is a plane vertical with described inner edge, the end face of described another claw hook also is the plane, this plane and described major axis are 45, its point is circular-arc, and its radius is (0.3～0.4) with the ratio of described major axis: (10.7～11.25); The common tangent line of the outer rim of described two claw hooks is parallel with described major axis; Described son button cross-sectional plane is an asymmetric arrow shaped, and it is positioned at its both sides by straight arrow shaft partial sum and the asymmetric wing of two of being attached thereto portion constitutes; The width of described arrow shaft part is (0.8～1.2) with the ratio of described major axis: (10.7～11.25), and its length is (4.9～5.2) with the ratio of described major axis: (10.7～11.25); The inner edge of a described wing portion and arrow shaft portion line of centers are 42 °～43 ° angle, the outer rim of this wing portion and this line of centers are 39 °～41 ° angles, described inner edge top with draw from arrow, the distance of the line parallel with major axis is (2.05～2.25) with the ratio of described major axis: (10.7～11.25), the top of this wing are a plane vertical with inner edge; The inner edge of described another wing portion and arrow shaft portion line of centers are 49 °～50 ° angle, its outer rim and this line of centers are 30 °～32 ° angle, and this wing portion end points is (1.8～2.0) with the ratio that draws from the distance of the parallel lines that is parallel to described major axis of arrow end and described major axis: (10.7～11.25).