簡單的熱封方法手工熱封法：常用于PE、PP單一薄膜熱封。

Simple heat sealing method: manual heat sealing method: commonly used for PE and PP single film heat sealing.

熱封時需要借助于耐熱薄膜將普通電烙鐵刀口部位彎成“L”形，刀口寬度一般為3mm，再將導(dǎo)線接通在調(diào)壓器上進行恒溫控制。薄膜在封口處留一個邊，則熱封強度會更大些。實際操作時，鋪2層細平布，再鋪一層不易變形的卡其布，布紋應(yīng)與熱封線呈45°或平直，其作用是使熱封部位產(chǎn)生均勻的花紋，以強化花紋(起到筋骨支撐的作用)結(jié)構(gòu)來達到分子間互相滲透的目的，提高封口界面的密封性。

During heat sealing, it is necessary to bend the knife edge of ordinary electric soldering iron into "L" shape with the help of heat-resistant film, the width of the knife edge is generally 3mm, and then connect the wire to the voltage regulator for constant temperature control. If the film leaves an edge at the seal, the heat sealing strength will be greater. During actual operation, lay two layers of fine plain cloth, and then lay a layer of non-deformable khaki cloth. The cloth pattern should be 45 ° or straight with the heat sealing line. Its function is to make the heat sealing part produce uniform patterns, so as to strengthen the pattern (play the role of rib support) structure to achieve the purpose of mutual penetration between molecules and improve the sealing of the sealing interface.

依靠外部加熱實現(xiàn)熱封的熱板熱封法：先將兩層重疊的薄膜放在兩塊加熱(或者其中一塊加熱)的金屬板之間，直到表層熔化，然后在壓力下使熔化的表面迅速結(jié)合在一起，并保持壓力冷卻為止。熱板熱封裝置結(jié)構(gòu)簡單，成本低，壽命長，且不易損壞。

Hot plate heat sealing method relying on external heating: first place two overlapping films between two heated (or one heated) metal plates until the surface layer melts, and then quickly combine the melted surfaces under pressure and keep the pressure until cooling. The hot plate heat sealing device has simple structure, low cost, long service life and is not easy to be damaged.

此外，還有一種熱空氣熱封法，這種方法就是借助熱氣，將其吹向塑料薄膜表面進行熱封，此法可應(yīng)用于重包裝的熱封。

In addition, there is also a hot air heat sealing method. This method is to use hot air to blow it to the surface of plastic film for heat sealing. This method can be applied to the heat sealing of heavy packaging.

人們在選購塑料包裝袋的時候，許多人會下意識的挑選厚而牢固的包裝袋，并且人們一般覺得越厚的包裝袋品質(zhì)越高，可是事實上并非越厚越牢固的包裝袋越高。由于對塑料包裝袋的制做規(guī)定是有很嚴苛的規(guī)范的，非常是用在食品包裝上的塑料袋，是一定要采用靠譜生產(chǎn)廠家所生產(chǎn)的，會有有關(guān)部門開展審核的合格工藝品。

When people buy plastic packaging bags, many people will subconsciously choose thick and strong packaging bags, and people generally think that the thicker the packaging bags, the higher the quality, but in fact, the thicker and stronger the packaging bags, the higher the quality. Because the state has strict regulations on the production of plastic packaging bags, especially plastic bags used in food packaging, must be produced by reliable manufacturers, and will be reviewed by relevant departments.

食品用的塑料袋務(wù)必標(biāo)明有“食品專用型”和“QS標(biāo)示”這類的標(biāo)字。此外，可以沖著光源能夠看見塑料袋是不是整潔。由于合格的膠袋是很整潔、沒有雜質(zhì)的，殊不知偽劣的塑料袋就會見到有臟點、雜質(zhì)。這都是人們平時在選購時能夠直觀分辨塑料袋品質(zhì)的一種好方式呢。

The plastic bags used for food must be marked with "food special type" and "QS mark". In addition, you can see whether the plastic bag is clean by looking at the light source. As the qualified plastic bags are clean and free of impurities, it is hardly surprising that the fake and inferior plastic bags will have dirty spots and impurities. This is a good way for people to visually distinguish the quality of plastic bags when shopping.