Discussion on the technology and quality index of

Discussion on the technology and quality index of base paper for honeycomb paperboard

honeycomb paperboard is a new material that has been converted from military to civil production since the early 1990s, and has a wide range of uses. Honeycomb paperboard needs two main types of raw materials, paper and paperboard and glue

I. product standards of paper industry

at present, there are more than 5000 varieties of paper and paperboard in China, including more than 160 national standards or industry standards, and the rest are enterprise standards or agreement standards. Because "honeycomb paperboard" has a short history of domestic production, there is no special base paper and its product standards. The gb/ti adopted in the "draft for approval" is the standard of corrugated base paper, which is used for the quality control of honeycomb core, gb/ti is the standard of carton board, which is used for the quality control of honeycomb face paper (see Annexes I and II). I think it can only be used as a reference, because the purpose of honeycomb paperboard and carton is different. According to the quality needs of honeycomb core and face paper, we should have our own indicators and numerical requirements

I have participated in honeycomb paperboard meetings several times and learned from the communication with some manufacturers that some manufacturers use imported base paper and semi-finished products for "honeycomb core"; There are also some domestic carton paper and corrugated base paper, which generally reflect that the strength of domestic base paper is not enough to meet the special requirements for paperboard for different purposes. For example, the paper pallets for export products are mostly transported by sea, the water absorption index of Grade A in the carton paper standard is 35.0/50g/m2 positive/negative, the analysis shows that the American face paper is only 3.0g/m2, the domestic face selection paper is mostly in C, D, etc., and the water absorption index of grade C is only 60.0g/m2 positive, and the reverse is not controlled. The standard of corrugated base paper is of great significance to improve the technical level and automation level of China's aluminum purification industry. This index has not been stipulated in the standard. The tray should be moisture-proof and moisture-proof to prevent seawater immersion. Most manufacturers prefer to add additives in the process of paperboard production (the additives of imported paper trays are added to pulp) by adding additives in the process of base paper production or coating additives on the surface of paper trays in the process of use; The "honeycomb" used in construction shall also be treated with anti-corrosion treatment. The imported samples were analyzed and found that 100% chemical wood pulp was used for the face paper, and 100% water fibrosis machine pulp was used for the core paper. Because the imported samples analyzed were finished products, a lot of glue was stuck on the face paper, and the core paper size was small, so more index values could not be tested

recently, fourteen paper samples were taken from the paper and paperboard used by Beijing Zhidian composite Co., Ltd. for testing and physical index analysis, and three of them were used to further analyze the fiber ratio, fiber density and other indicators. Eight samples were marked with the method of sizing. There are five single blood sizing. The British government announced that it would invest 50million pounds (1 pound or about US $1.52) to support graphene research. Three pieces of sizing were stopped, and the dry and wet strength of paper samples were further tested to observe the strength reduction of paper and paperboard after soaking in water. The strength reduction rate of single-sided sizing paper samples was 85 5%, double-sided sizing paper 4 Is the software problem sample strength reduction rate at 72 5%, the strength reduction rate of double-sided sizing paper sample is 72 Between 8%, very regular. The above figures show that the strength retention rate of double-sided sizing paper sample is higher than that of single-sided sizing paper after soaking. Through the fiber ratio analysis, the three paper samples are produced by using secondary fibers. The paper samples contain chemical pulp and mechanical pulp. The more chemical pulp, the higher the strength of paper and paperboard; When the ratio of wood pulp and straw pulp is used, the more the content of wood pulp, the higher the strength of paper and paperboard; The longer the fiber length, the higher the strength of paper and paperboard

II. Quality requirements of base paper for honeycomb paperboard

1. Honeycomb paperboard belongs to the scope of paper products

the quantity of packaging paper and paperboard accounts for about 50% in the paper industry, and there are a large number of imports every year. In 2000, packaging paper and paperboard accounted for 72.9% of the total imports, an increase of 10 percentage points in two years. The main varieties are kraft paper, paper bag paper, carton board, whiteboard, white cardboard, Coated Whiteboard, corrugated base paper, etc., and the above varieties have product standards. These varieties are mainly supplied to the packaging industry to produce cartons, paper barrels, cartons, paper cups, paper bowls, etc

China's product packaging methods are mainly paper packaging, glass packaging, plastic packaging and metal packaging, while paper packaging accounts for about 50% and Taiwan Province accounts for 70%. The amount of packaging paper can also reflect the industrial level of a country. For example, the output of packaging paper and paperboard in the United States accounted for 62.8% of the total in 1998

it can be seen that "bee channeling" paperboard should belong to the scope of paper products

2, "honeycomb" paperboard structure

"honeycomb" paperboard is formed by bonding two layers of face paper with the middle "honeycomb" paper core

"honeycomb" paper core is made of a variety of materials, including aluminum foil, paper and paperboard, glass cloth or other soft materials, and then bonded with paperboard or metal plate, plywood, fiberboard, decorative board, resin board, glass steel plate, gypsum board and cement board on both sides of the "honeycomb" paper core

3. The application scope of "honeycomb" paperboard

"honeycomb" paperboard has a wide range of applications. At present, the developed application fields include the following aspects:

-- replacing the packaging of wooden boxes and pallets for export commodities

-- as buffer, partition and cushion packaging

-- storage and transportation of disposable turnover pallets:

-- building materials, which are used to replace wood, metal plates, decorative plates, ceilings, floors, movable boards and other honeycomb sandwich boards. Gypsum boards are used to make interior walls and can replace clay bricks

-- household wardrobe, bookcase, bookshelf, billiard table

-- vehicle and marine materials such as hatch plate, deck and bulkhead

-- billboards and display boards

-- sanitary coffin for funeral cremation

with the continuous development of industry, honeycomb paperboard will be adopted in more packaging fields. Different uses have different requirements for the quality of their raw materials

4, "honeycomb" paperboard on the quality of base paper

"honeycomb" paperboard base paper has similarities with box paperboard, but also has its own special requirements. Its quality indicators can be formulated with reference to the indicators of corrugated base paper and box paperboard, The following points should be considered in the good method of standard curing hydraulic universal testing machine:

(1) base paper name

face paper - "honeycomb" face paper

core paper - "honeycomb" core paper

(2) base paper index

"honeycomb" face paper index: quantitative, tightness, fracture length, bursting index * ring pressure index, * folding resistance, water absorption (positive/negative), delivery moisture

note: when using "honeycomb" paperboard to produce packaging boxes, the gold index is added

"honeycomb" core paper indicators:

quantitative, tightness, folding resistance, transverse ring pressure index, water absorption (positive/negative), delivery moisture

Index Interpretation:

quantitative - the mass per square meter of paper or paperboard, expressed in g/m2

tightness - the weight per unit volume of paperboard calculated from the quantitative and single page thickness, expressed in g/m2

breaking length - the weight of the paper strip with the same width, and the length required to break the paper. It is quantitatively calculated from the tensile strength and the sample after constant temperature and humidity, and the unit is km

bursting index - the maximum pressure uniformly increased on the unit area of paper or paperboard causes the sample to crack, that is, the bursting resistance of the sample is divided by the sample after constant temperature and humidity, and the unit is kpa M2/g

folding resistance refers to the ability of paper or paperboard to withstand 135 degree reciprocating folding under a certain tension, expressed in the number of reciprocating folding, unit: times

water absorption - the value of water absorption (Cobb) on the surface of paper and paperboard, the amount of water absorbed by the surface of paper and paperboard per unit area within a specified time under certain pressure and temperature, expressed in g/m2 (positive/negative)

ring pressure index -- insert a certain size of paperboard sample into the sample seat to form a ring shape, and compress between the measuring plates on both sides. The maximum force that can be borne before compression is the ring pressure strength, divided by the constant temperature and humidity, and the sample quantity: n.m/g

delivery moisture - the content of water in paper or paperboard. When the sample is dried to constant weight according to the regulations, the ratio of the reduced weight to the weight of the original sample, expressed in%

(3) index grading

the paper industry standard implements hierarchical management, because the peak board has many uses, and it should also be graded

a - international advanced level

b - domestic advanced level

c - domestic general level

III. suggestions

1. "Honeycomb" paperboard should have a special base paper

"honeycomb" paperboard should have its own base paper. The fiber raw materials and index values used should be selected according to the purpose of the product, and the use of secondary fibers should not be emphasized. The raw materials of carton board range from 100% wood fiber to 100% grass fiber, and there are mixed fibers of wood and grass in different proportions. Generally speaking, the more wood fiber, the higher the strength of paperboard, and the more straw pulp, the opposite. Wood and grass have secondary fibers. Generally, imported American waste paper is used, and its content is mostly wood fiber, while domestic waste paper is mostly grass fiber. Of course, the price of imported raw materials will also be higher than the domestic price. Manufacturers should add different additives according to different uses, which should be made clear when the supplier and the demander order

2. The supply and demand sides should strengthen cooperation

the current conditions for formulating the standard of "honeycomb" paperboard base paper are not mature, and preparations have been made. In order to explore the index value, the imported products were analyzed, but because the samples were mostly finished products, small specifications and coated with glue, some indicators could not be tested. The manufacturer should also conduct a series of follow-up tests, which requires everyone to work together, actively cooperate, constantly accumulate data, and finally jointly formulate a practical base paper standard

3. The connection between the width of "honeycomb" paperboard machine and paper machine

society is a big cycle, and the products of this industry are the raw materials of another industry. The specification of honeycomb paperboard is based on the needs of users. In addition to ensuring the quality of products, there is also a specification problem, so the "honeycomb" paperboard machine also has a stereotype problem. At present, the paper machine produces paperboard with a width of 1600mm; 2400MM； A few are 1092mm, which are not matched with each other, which is bound to cause waste or increase product prices, which will be detrimental to both sides. It is suggested that both parties should consider the standardization of machine width in the future. (text/Li Yuhua, China Papermaking Research Institute) (from China Packaging News)