What is the current status of the development of bio-based coatings?

With the global warming, the melting of glaciers has accelerated, not only has forest fires intensified, but oil resources have also been depleted.

However, water-based coatings still use synthetic emulsions using petroleum monomers as raw materials, and it has become more important to seek other resources to replace petroleum as the source of raw materials for synthetic polymer materials.

01 The rise of biobased

Bio-based refers to the use of renewable materials, including crops, trees and other plants other than food and their residues and inclusions as raw materials, a new type of material manufactured through biological, chemical, and physical methods

In recent years, bio-based chemicals and produceable resources have become the focus of competition among large multinational companies.

Research on bio-based products and green energy has become the forefront of the world's scientific and technological fields, and countries all over the world are actively promoting it, which has also created a favorable space for the rapid expansion of its market

According to a USDA research report, by 2025, bio-based chemicals will occupy 22% of the global chemical market, and the output value of bio-based chemicals will exceed 500 billion US dollars per year

02Bio-based coatings that are ready to release

In China, the "Thirteenth Five-Year Bio-industry Development Plan", the "Thirteenth Five-Year Biotechnology Innovation Special Plan" and bio-manufacturing-related plans issued by relevant departments propose measures to accelerate the pace of innovation and development of the bio-industry and foster new driving forces for the bio-economy.

In the "National Bioeconomy Blueprint" put forward by the United States in 2012, the development of bio-based products is one of the main contents of the development of bioeconomy

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03Bio-based coating industry trends

Bio-based materials are mainly derived from plants.
There are many bio-based coating materials on the market, mainly water-based emulsified alkyd polymers extracted from vegetable oils and water-based dispersion polymers synthesized from bio-naphtha extracted from crop fermentation sugars
.

In 2017, BASF, Covestro and Audi worked together to develop the first automotive varnish made from bio-based curing agents
.
In the same year, PPG cooperated with DSM to launch the biodegradable bio-based interior wall paint-Sigma Air Pure
.

Covestro also launched a new type of curing agent "De smolur eco N7300", which is a PDI prepared from pentane diamine (PDA); PDA is made of feed corn starch, which is converted into feed corn starch by special microorganisms.
The synthesis of pentamethylene diisocyanate requires only two steps in the process, while the general petrochemical product HDI synthesis requires four steps.
The former has certain advantages over the latter in terms of performance, and the resin produced has a lower viscosity, which can replace HDI.
Made into high-performance polyurethane coatings
.

In addition, there are many precedents using bio-based technologies:

◆ Using bio-based renewable materials such as carbon dioxide, plants, etc.
to produce bio-based aniline, curing agents, solvents, etc.
, can reduce dependence on petroleum resources
.

◆Using cashew nut shell liquid to extract high-performance two-component room temperature curing curing agent for epoxy resin; the method is to perform Mannich reaction of cashew nut shell liquid with aldehydes and polyamines to prepare cardan phenolic aldehyde Amine curing agent can make epoxy resin be coated and cured into a film on low temperature, humid, and sometimes rusty metal surfaces, and its performance is better than the polyamide curing agent commonly used for epoxy resin
.
The curing agent has a rich source of raw materials, is cashew nut shells, and can be regenerated.
The curing agent is made of simple and convenient process and does not require special industrial equipment
.

◆ Epoxidized soybean oil/cottonseed oil/rapeseed oil can be added with acrylic acid to form a light-curing coating, and can be used as an epoxy reactive diluent to cure with amines, and can also be cured with acids and anhydrides.
The hydroxyl groups formed after ring opening It can be cured with an isocyanate resin or an amino group, reaction with carbon dioxide to generate cyclic carbonate, a primary amine can be reacted with a non-isocyanate-cured polyurethane resin and the like
.

Using corn, rice, sweet potato and other starchy raw materials, through biological fermentation, lactic acid is formed, and then under the action of a catalyst, lactide is synthesized, which can significantly shorten the drying time when used in alkyd resins.
It can also be used as a polyester raw material for development.
Ring polymerization to form a degradable resin
.

◆ Chen Li, Zhang Hanqing and others of Changzhou Paint Chemical Research Institute used dimer acid and bio-based material pentane diamine to synthesize a non-ionic water-based low-temperature epoxy curing agent
.
This new type of water-based polyamide curing agent is orange-yellow translucent liquid with moderate viscosity, long pot life and good stability.
It can be cured into a film at room temperature with water-based epoxy emulsion, and its coating film has good flexibility, Physical properties such as adhesion, pencil hardness, and chemical stability such as water resistance, acid and alkali resistance, salt spray resistance, etc.
, can be used in industrial anti-corrosion fields such as water-based epoxy floors, auto parts, and construction machinery
.

◆ Recently, Fraunhofer Institute of Applied Polymer successfully developed based on renewable raw materials made of potato starch and other renewable anti-corrosion coatings, protective coatings may be used metal materials and fire doors, computer housings and other objects
.

◆ In China, Shenzhen Haichuan New Material uses natural renewable materials, and after special biological modification technology, it has developed a bio-based natural water-based dispersion-Haichuan Natural Plant Herbal Emulsion
.
The emulsion is mainly modified vegetable oil, of which the content of polymerized natural vegetable oil accounts for 60%-80%; it has the characteristics of renewable raw materials and biodegradable products.
The degraded product is environmentally friendly, has no pollution to the environment, and has excellent emulsion performance.
It can replace petroleum-based emulsions and is widely used in water-based coatings and inks
.

04 Research and development of bio-based coatings

In Europe, due to higher prices and increased demand, bio-based coatings are becoming more and more popular.
The demand for bio-based coatings varies greatly between different regions in Europe
.

Two of these countries are more prominent, but the reasons are completely different
.
The first is in the Netherlands.
In July 2016, the country implemented a sustainable development public bidding procurement catalog, which stated: “The higher the ratio of bio-based raw materials and recyclable raw materials in the supplied products, the higher the price
.
” This It is more conducive to consider bio-based solutions
.
The catalog is suitable for various projects, including road construction, offshore projects, landscaping, and construction
.

Second, in Switzerland, another approach was adopted
.
A labeling system is used to ensure the sale of paints and varnishes based on renewable raw materials
.
To obtain the highest level of the two types of labels in the Swiss environmental label, it is necessary to prove that the paints and varnishes produced contain 95% renewable raw materials
.
The label also grants adhesives, wood preservatives, plasters and fillers
.
The label also sets minimum performance requirements (such as wet abrasion resistance or contrast ratio) to ensure high acceptance among users
.

In China, the research and development of bio-based coatings also emerge in endlessly:

◆ Sankeshu easy-to-clean interior wall paint Recently, Sankeshu paint invented a "plant-based anti-formaldehyde, antibacterial and easy-to-clean interior wall paint"
.
The plant-based emulsion in the present invention is mainly composed of wood fibers extracted from plant straws to obtain bio-based monomers after fermentation and filtration, and introduce ketone structures through emulsion polymerization to prepare bio-based emulsions
.

The invention uses plant-based emulsions, chlorinated titanium dioxide, lamellar talc, silica powder, etc.
to synergize to form a relatively dense surface structure, which can significantly improve the stain resistance and scrubbing resistance of the wall paint, and the scrubbing resistance is higher than 30,000 Times
.
It makes up for the gap in the application of plant-based emulsions in anti-fouling and formaldehyde removal in the field of wall paint
.

It is reported that the plant-based emulsion used in this invention contains more than 34% of plant-derived materials, which can effectively reduce the use of mineral petroleum and kerosene-based materials.
It is reproducible, easy to degrade, environmentally friendly, and harmless to humans.
Features
.

◆ Dulux Breathing Natural Plant Lacquer This product replaces part of the petroleum derivatives in the emulsion by extracting the edible parts of plants such as corn and cassava to ensure the natural safety of the ingredients from the source
.

◆ Nippon Original Plant Extract Paint This product adopts the new technology "Biomass Balonce Approach", which replaces 100% of the petroleum resources used in the production process of the original plant extract paint with palm, a renewable resource from Nordic forests After use, the performance of the coating can be kept unchanged
.

◆ Chenyang Zhirun Children's Paint In May 2020, Chenyang Paint launched the newly developed Zhirun Children's Water Paint
.
This product is jointly developed by Chenyang Water Paint and DSM (DSM).
It uses plant-based emulsions and is rich in natural plant ingredients.
It uses safer plant renewable resources to replace the petroleum resources (bio-based substance content) in the paint.
30% or more), after nearly three years of research and development, more than 20,000 repeated trials have broken through the compatibility of plant-based raw material technology with Chenyang water paint's odor-cleaning, anti-fouling and other core technologies
.

◆ PPG bio-based interior wall paint This product is based on DSM's De covery bio-based technology.
By using this resin technology platform, a resin that meets the specific requirements of PPG's Sig ma Air pure vision has been developed
.
The resin is made from renewable resources such as sugar, natural oil, corn starch and agricultural waste
.
These natural materials have largely replaced petroleum products used in traditional solvent-based and water-based paint binder resins
.

05Development relationship of bio-based coatings

It should be noted that not all raw materials from renewable resources are sustainable
.
Choosing any renewable material and switching to it is not the right way.
It is essential to avoid competition between raw materials and food and feed production
.
A few years ago, the European Commission recognized the need to promote the development of a bio-based circular economy, and together with the chemical industry launched the EU Bio-based Industry Joint Program (BBI-JU)
.
Since 2014, this 3.
7 billion euro government-social capital cooperation program has been committed to the development of bio-based raw materials, but there are still some issues affecting sustainable development
.

Experts believe that the current development of bio-based coatings may be affected, but in the long run, this is also a huge opportunity to turn crises into opportunities and promote value chain strategies
.
Many countries are evaluating and adopting specific plans and proposing ways to stimulate their own economies.
Some of these plans are aimed at promoting sustainable development solutions.
This will be a great opportunity
.
Based on this, when making a decision, you need to consider the cost-performance-sustainability triangle relationship
.

One factor is cost
.
Oil is a raw material with very large price fluctuations.
Of course, renewable raw materials are also susceptible to price fluctuations, but these fluctuations are usually not so obvious
.
In a short period of time, cost is still an important factor restricting the scale development of bio-based coatings
.

Another factor is performance issues
.
For bio-based coatings to develop on a large scale, there are not only cost challenges, but also application challenges
.
Because bio-based coatings are mostly taken from natural plants, such as soybean oil and castor oil, they cannot avoid color problems and are not suitable for varnishes.
Also, because of their relatively high viscosity, there will be some defects in construction
.

In the short term, if companies still use raw materials on the principle of direct substitution, it will be inconvenient to use existing equipment for petrochemical raw materials to produce bio-based raw materials
.
BASF is the main company adopting the biomass balance process, which provides the opportunity for fast and inexpensive conversion
.
Experts pointed out that when the materials and quality remain unchanged, customers will immediately switch to products that use the biomass balance process without re-certification
.

The BBU-JU Federation stated that from 2010 to 2015, the overall use of biomass used to produce materials increased by 5.
6%; among them, the bio-based chemicals sector achieved the highest relative growth rate (up 48.
4%)
.
If we continue to develop at this speed, we will see a greener paint industry
.
In the future, if bio-based raw materials are competitive in technical performance and can provide more performance than just "green or sustainable development", then bio-based raw materials can gain a reasonable market position
.

At present, PPG, Nippon, Chenyang, Sankeshu, etc.
have all launched bio-based coatings on the market.
It is not clear what the certification standards for "bio-based" of these new coatings are
.
It is reported that Chenyang Plant Moisturizing Paint and Dulux Breathing Planting Paint have passed the bio-based certification of the United States Department of Agriculture; Nippon Natural Plant Extract Paint is the first renewable resource certification certificate of TUV SUD in China.

.

So far, the standard for bio-based coatings is still the standard for general coatings
.
On October 15, 2020, the Ministry of Industry and Information Technology of China announced 545 industry standards, 33 recommended national standards, and 10 foreign language versions of industry standards.
These projects include plans for CNOOC Changzhou Paint & Chemical Research Institute Co.
, Ltd.
, Dow Chemical (China) The industry standard of "Bio-based Emulsion Interior Wall Coatings" drafted by the company is listed.
This standard is a recommended standard and is planned to be completed in 2021
.

06 Conclusion

In the context of intensified global climate change, mankind should find solutions that are compatible with development and control carbon emissions
.
In September 2020, China announced “strive to reach the peak of carbon dioxide emissions by 2030, and strive to achieve carbon neutrality by 2060”
.
Low-carbonization will be a very strict reversing mechanism for us to transform our economic development mode, and its impact on China's economic structure and technological choices will be subversive
.

Bio-based polymer materials play a major role in supporting the realization of the national carbon neutral strategy due to their carbon reduction and carbon fixation effects
.
Although bio-based coatings have not been widely used in the industry and are still in the early stages of development, they are still an important step towards sustainable development of coating processes
.
In the long run, the development of new bio-based raw materials is very important; especially compared with traditional coatings, these bio-based coatings have superior performance and will gradually dominate the market
.
The author believes that under environmental pressure and policy guidance, the coatings industry will gradually move in this direction
.
This bud of bio-based coatings is bound to bloom and bloom throughout the industry
.