What Is a Retort Pouch?

The cooking bag is a kind of composite plastic film bag that can be heat treated. It has the advantages of both a canned container and a boiling water resistant plastic bag. After more than ten years of use, it is an ideal sales packaging container.

The cooking bag is made of three layers of materials. The typical cooking bag structure is: the outer layer is a polyester film for reinforcement; the middle layer is

Inspection of raw materials

a. Film (aluminum foil) thickness (per GB 6672), tensile strength & elongation (per GB 13022-91), wetting tension (per GB 10003-88), oxygen / moisture permeability (per GB 1038/1037) Carried out), high temperature resistance, sanitary suitability (in accordance with GB-9687-88), appearance;

b. High temperature resistance of adhesives and inks, food hygiene suitability;

Inspection of film (aluminum foil) lamination process

a. Appearance (no obvious defects such as wrinkles and delamination);

b. Compound speed, viscosity of glue:

The measured value is different according to the different adhesives and proportions;

c. Testing of glue amount:

Use coated paper (or self-adhesive glossy paper), divide left, middle and right into three different positions, put in the middle of the two layers of film to be compounded, remove the sample after compounding. Then use an area square of 100mm100mm to cut the measurement samples at three different positions left, center and right; then remove the coated paper (or self-adhesive paper), put the coated film on the electronic scale and weigh it Note the weight a. Then put the weighed film (coated side with glue) into the solvent (EA) to wash and remove the glue solution, and then put it on the electronic scale to weigh and record the weight b. ab is the coating amount of the sample, and then it can be converted into a unit of g / m2.

d. Control of curing temperature and time after compounding:

Set the corresponding temperature and time according to the raw materials used;

e. Composite strength between cured composite membranes (per 8880-88);

Cut the left, middle and right three test pieces, the width of the test piece is 15mm, the length is about 15cm, the layer to be tested is separated from the layer by about 15mm, and fixed on the upper and lower fixtures of the LDX-200 universal material testing machine, respectively. The tensile speed was adjusted to 100 mm / min for measurement.

f. Amount of residual solvent:

Cut a 0.2m2 sample, quickly cut the sample into 10mm30mm pieces, put it into a clean approximately 500ml conical bottle preheated at 80 ° C, seal it with a silicone plug, and put it in a 80 ° C incubator for 30 minutes. Using a 5ml syringe, take a gas sample from a 1ml bottle and inject it into a 2061C gas chromatograph for measurement. The result is 10mg / m2.

Film material:

Polyester: has excellent transparency. Heat resistance and wear resistance. The film thickness is 12 microns and 25 microns. Printing is done on polyester. It can be used as a sacrificial bag for cooking bags or tray-shaped cellars.
Nylon: Indispensable as a base material for packaging materials for soft cans. There are two types of biaxially stretched and unstretched, biaxially stretched nylon. The film not only has excellent heat resistance and cold resistance, but also has good tear strength and pinhole resistance. Therefore, it can be used together with other raw materials. In addition, in order to prevent curling and improve strength, there are also nylon 6-6 films, but the price is higher than nylon 6.

Polyvinylidene chloride: As a single-layer film, it can also be used in soft cans. It can be used as a packaging material for ham intestines. Its sealing, ligation, heat-shrinkable gas barrier properties are excellent. Polyvinylidene chloride can also be used as a dissolution layer of pancreatic material such as nylon polyfluorene. In addition, there are excellent substrates for high-temperature and high-pressure polyvinylidene chloride thin pancreas used as a composite substrate for cooking bags;
High-density polyethylene: Special high-density polyethylene has been sold in Japan. Although this film has poor gas field barrier properties, it can be used as a sealing layer due to its tensile strength, excellent elongation, tear strength, and good sealing adaptability. However, high-density polyethylene has several characteristics in terms of heat resistance, and its maximum heat-resistant temperature is 120 ° C.
Polypropylene: It has good transparency, oil resistance, and better heat resistance than special polyethylene, so it can be used as a sealing layer for cooking bags and cooking cellars. The sealing of soft can packaging materials is often made of stretched polypropylene or sheet.
Aluminum foil: Aluminum foil is made by rolling electrolytic aluminum with a purity of more than clams. It is the only metal substrate in packaging materials when used as a packaging material. Because aluminum foil is non-toxic, it has excellent light shielding and high moisture resistance. , Gas barrier and confidentiality, can most effectively protect the packaged material, so it is most suitable as a packaging material for fatty foods. ^[1]

Inspection of the bag making process

a. Size of bag making and edge sealing (according to customer requirements);

b. Heat-sealing strength

Use a steel ruler to cut a 15mm wide test piece from the side seal of the bag. (The number and position of the test pieces vary according to the area and shape of the bag. The length of the sample depends on the size of the bag.) LDX-200 universal material testing machine measures the heat seal strength on the upper and lower fixtures. )

C. Fill the bag with water of the same volume and seal it. Place the bag sample between the upper and lower plates of the pressure gauge, perform pressure detection according to the conditions (pressure, time) required by the customer, and observe whether the bag is broken or leaking.

d. Residual solvent content (same as inspection item f of the above composite process):

High temperature cooking resistance check

After making the bag, fill the bag with the same volume of content and seal it tightly (note: the content should be similar to the content specified by the customer, and should not be replaced by water or other substances, and the air in the bag should be exhausted as much as possible when sealing In order to avoid the effect of air expansion during cooking, test results), put into the ts-25c back pressure high temperature cooking pot, set the conditions (cooking temperature, time, pressure) required by the customer for high temperature cooking resistance test; high temperature cooking bag The manufacturing process is currently the world's most retort bags. Most of them are made by dry lamination. A few can also be made by solvent-free lamination or co-extrusion lamination ^[2] .

Appearance inspection after cooking: The bag surface should be flat, no wrinkles, blistering, deformation, no delamination, leakage; if any of these undesirable phenomena, it is unqualified.