3. Composite packaging material is a multi-layer structure composed of several substrates with different properties through lamination, extrusion veneer and * * * extrusion, so as to meet the requirements of transportation, storage and sales for packaging functions and the special requirements of some products.
4. Wet bonding lamination-refers to the process of adding any liquid adhesive to the base material, and then immediately compounding it with the second layer material, thus making the laminated material.
5. Chemical pulping-chemical solution is used to dissolve lignin and other impurities in wood chips at a certain temperature and pressure, so as to keep cellulose as much as possible, prevent it from being destroyed as much as possible, and keep hemicellulose properly at the same time.
6. Burst resistance-the maximum pressure that a certain area of paper or cardboard can bear when it is pressed at a constant speed until it breaks. Expressed as hydraulic or pneumatic.
7. Tearing degree-refers to the work required to cut the paper or cardboard sample into a certain length in advance and then tear it into a certain length from the crack.
8. Ring compressive strength —— At a certain speed, the ring sample is compressed in parallel, and the pressure gradually increases to the pressure when the sample collapses.
9. Edge compressive strength-the compressive strength of corrugated board after standing up and pressing on both sides.
10. Flat compressive strength-refers to the ability to resist plane load perpendicular to corrugated board.
1 1. Degree of polymerization-the number of repeating structural units in the macromolecular chain.
12. Thermoplastics-linear and branched polymers.
13. Thermosetting plastics can become sticky at a certain temperature, but will not soften and melt after heating and molding for a certain time.
14. engineering plastics-plastics with high mechanical strength and rigidity are often used to manufacture mechanical parts or engineering structures instead of steel or nonferrous metals.
15. addition polymerization-a reaction in which one or more monomers are combined with each other through an addition reaction to form a polymer.
16. Polycondensation-A reaction in which one or more monomers containing two or more identical or different functional groups are condensed with each other to form condensates, and other low-molecular-weight substances are also generated.
17. Homopolymerization-polycondensation of monomers containing two or more functional groups.
18.*** Polycondensation of two (or more) monomers with different functional groups.
19. Glass transition temperature-the highest temperature at which a polymer exhibits a glassy state.
20. Elastic modulus-the stress of the material when unit strain occurs.
2 1. Creep-Under the action of constant temperature and small external force, the deformation of the material gradually decreases with the increase of time.
22. Stress relaxation-Under the condition of constant temperature and deformation, the stress in the polymer gradually decreases with time.
23. "Aging" of polymers-degradation of physical, chemical and mechanical properties of polymer materials during processing, storage and use.
24. Thermoplastic polyester-linear saturated thermoplastic polyester, commonly known as thermoplastic polyester, can be formed by polycondensation of saturated dibasic acid and diol.
25. Clarifier-A substance that can evaporate or decompose the gas released by itself at high temperature to promote the discharge of bubbles in glass is called a clarifier.
26. Thermal stress-the stress caused by uneven temperature due to inconsistent heating or cooling rates of various parts of glass is called thermal stress.
27. Structural stress-the stress caused by defects such as uneven chemical composition, stripes, bumps and stones during melting is called structural stress.
28. Physical decolorization-adding a certain amount of colorant that can produce complementary colors to glass is called physical decolorization.