Textile enterprises without PVA sizing: environmental protection solution in the cost category

After Premier Wen Jiabao presided over the meeting on energy saving and emission reduction this year, energy saving and emission reduction was brought to a new height. In this context, the National Cotton Textile Scientific and Technological Information Center of the organizer of the seminar finally selected the topic of “No PVA Green Pulp and Low-cost Energy-saving Sizing” as the subject of research. This is not only an accurate measure of the current status of the sizing industry but also A public advocacy for the implementation of energy-saving emission reduction processes and products is quite painstaking and profound.

The corporate representatives came to the meeting with a lot of questions this time. What paste is used to replace PVA slurry? How to solve some of the process problems in the sizing process? The atmosphere of the discussion was warm and open. The participants tried to "borrow brains" to peers, experts and scholars without seeking to abandon cost control, and sought out environmentally friendly production process solutions suited to their own companies.

What to replace PVA?

PVA-free sizing is a concept of environmental sizing proposed by the China Cotton Textile Industry Association as early as 1997. With the enhancement of people’s environmental awareness, the introduction of the national energy conservation and emission reduction policy, and the restriction on the import of PVA-containing pulp fabrics in developed regions such as Europe, the problem of no-PVA sizing has gradually moved from an ideal state into the development reality of the company.

At present, a number of high-performance slurries that have replaced PVA sizing have been developed in the country, and can partially or completely replace PVA in the sizing of cotton high-segment and polyester-cotton products, and have achieved certain practical experience.

It is understood that almost all major textile companies participating in the seminar have adopted PVA-free stock formulations for production.

“At present, large-scale textile companies generally use a mixed-slurry model of modified starch plus polyacrylic acid,” an industry insider told reporters. He believes that polyacrylic acid is an ideal alternative to PVA, but because of its high price, it is rarely used as a single-component slurry.

According to Professor Zhang Xiaodong, deputy director of the School of Environmental and Chemical Engineering at Qingdao University, the industry's current development and application of green environmental protection slurry mainly revolves around modified starch and polyacrylic acid slurry. At present, the third-generation modified starch is a grafted and modified starch, which is mainly used as a grafting monomer with a vinyl monomer such as a propylene ester, so as to reduce the viscosity of the starch to meet the low viscosity requirement of the sizing process.

Zhang Xiaodong also revealed that in early June of this year, the Ministry of Science and Technology had taken the lead in establishing a grafted and modified starch project with a total investment of 96 million yuan, of which the state invested 40 million yuan.

Liu Dengke, a senior engineer of Fujian Jiada Textile Co., Ltd., believes that the formulation of the slurry should be determined based on factors such as the degree of difficulty of the fabric, the yarn support, the type of yarn, the properties of the slurry, and the type of loom. This realistic viewpoint won the recognition of many participants.

However, due to the uneven distribution of domestic ordinary modified starch production enterprises, some “modified starches that are almost the same as the original starch are interfering with normal work processes.” Liu Dengke suggested that slurry companies can provide inspection reports of professional inspection agencies in the future. With each shipment, the self-inspection certificate of the characteristic index is provided.

The cost is everything?

In the field of textile auxiliaries, the “Three E” principle is prevalent. That is, environmental textile auxiliaries should follow Efficiency, Economy, and Ecology. In the case of pulp, economics is a key factor in determining whether a company chooses or abandons PVA.

"With the temporary decline in PVA prices, textile mills are facing the global economic recession and the textile industry's sluggish double-difficult situation, in order to survive, to crisis, pay more attention to the cost of sizing, some factories have resumed the use of PVA," Luoyang Wu Qing, a representative of the Baima Group Co., Ltd., said: “In order to adhere to the phased results that have been achieved without PVA sizing, we must do a good job in process optimization and control sizing costs.”

How to control the cost? Wu Qing believes that it is possible to optimize the slurry formulation and replace the higher-priced starch with a starch with a similar performance and lower price, and reduce the cost of pulp under the premise of stable quality.

The discussion on modified starch and polyacrylic acid at the seminar can be said to be the branch of the school under the view of replacing PVA. What really stirs up the debate among delegates is whether or not nanopaste can be used as a substitute for PVA.

A Suzhou representative of a nano-slurry company believes that the bio-toxicity of nano-materials needs to be further researched and demonstrated. In the future, it is hoped that the pulp industry can also solicit the opinions of some nano-material experts.

However, the view that the nanopaste is not suitable is that non-toxic oxides show a high degree of activity and show a related toxic effect when they are in the nanoscale range, whereas the human immune system cannot detect nanosized cells smaller than the virus. Substances, so use nanometers carefully.

If you explore the topic from the perspective of high-end science, it is undoubtedly a test of human wisdom. However, if we understand this debate from the perspective of cost, everything becomes clear.

According to the reporter's knowledge, nano-sized slurry is a kind of slurry with a relatively high cost performance, so it has a market in many small and medium-sized textile enterprises. The focus of the problem seems to have returned to costs.

Wang Zhenghu, senior engineer of Shanghai Fufang Textile Consultation Center, asserted in the discussion that the current situation of nanosize slurries is to be completely banned from some difficulties, unless another inexpensive PVA-free paste is available, and the survival of the fittest on the market is to allow nanosize slurries. The only way to fade out.

With the innovation of sizing machinery, energy-saving sizing technologies such as pre-wetting sizing, wet twist-twisting and “two-high and one low” have been applied in textile enterprises, reducing the sizing rate, effectively sticking hairiness, and reducing the weaving process. The sizing and the improvement of weaving efficiency have achieved good results, and at the same time, the sizing cost has also been reduced.

At the seminar, Xiao Hanbin, chief engineer of Wuhan No.1 Cotton Group Co., Ltd., conducted an interactive question and answer on specific issues encountered in the application of pre-wetting sizing.

Experts stated that in the future production of the company, it is necessary to carry out technological transformation of some old equipment in combination with its own situation, so as to make it more in line with the needs of the modern sizing process; in addition, the performance of the slurry should be reasonably analyzed according to the difficulty of fabric production, and the design conforms to The optimal slurry composition of the weaving process, through the optimization of the process technology, reduces the requirements for weaving on the sizing quality and achieves the goal of reducing the sizing cost.