Issue 36/2012 - Production and application of environmentally friendly plasticizer ATBC

Tributyl acetyl citrate (ATBC) is non-toxic, tasteless, with mildew resistance environmental protection plasticizer, its low temperature flexibility is good, melting and sealing thermal stability is good, not easy to change color, oil resistance and light resistance, and most cellulose, polyvinyl chloride, polyvinyl acetate, etc.
have good compatibility, mainly used as cellulose ester and vinyl resin plasticizer
.
At present, China's plasticizer varieties are few, low quality, large demand, ATBC as a plasticizer with excellent performance, has considerable development prospects
.

First, the production process

The production method of ATBC generally uses citric acid and n-butanol for esterification reaction to obtain tributyl citrate, and then reacts with acetic anhydride to obtain crude products, and then conducts filtration rectification washing and other processes to obtain products
.
The synthesis route of this product is relatively simple, domestic research mainly focuses on synthesis, while synthetic research focuses on the difference of catalysts, and foreign research focuses on applications
.
At present, the synthesis of ATBC in industrial production adopts batch acylation process, and its catalyst can use concentrated sulfuric acid and other inorganic acids, inorganic acids or converted into H-type cation exchange resin, p-toluenesulfonic acid, sulfamic acid, etc.
, but there are problems such as
complex process, short service life of catalysts, high production costs, and low equipment utilization.

Foreign countries have been developing citrate for more than 30 years, and are produced
in the United States, France, the Netherlands, Japan and other countries.
The research of citrate products in China started relatively late, and only a few enterprises have industrial production
.
In 2010, Jiangsu Tianyin Chemical Co.
, Ltd.
successfully developed an ATBC continuous acylation production process, using the solid acid of the composite reinforced macroporous polystyrene sulfonic acid strong acid cation exchange resin as a catalyst
.
After mixing tributyl citrate with acetic anhydride and preheating, it enters the fixed-bed reactor filled with catalyst for acylation reaction; The post-treatment of acylation products adopts the common methods of prior art, including deacidification, neutralization, water washing, distillation, decolorization, filtration and other steps of acylation products to obtain ATBC finished products
.
This process has high yield, excellent quality and good
stability.
Tianyin Chemical Co.
, Ltd.
will build a 10,000-ton ATBC production plant in Binhai, Jiangsu Province to achieve continuous production
.

Second, market application

The biggest feature of ATBC is non-toxic and odorless, which can be used as a non-toxic plasticizer for PVC granulation, used as food packaging containers, children's toy products, medical products, and films, plates, cellulose coatings, etc
.

1.
Food packaging ATBC due to low toxicity, has been widely used in foreign food packaging industry, Britain, the United States, Germany, France, Italy, Japan, the Netherlands, etc.
have licensed ATBC for food packaging
materials, mainly used for plasticized PVC and vinylidene chloride copolymer (PVDC).

A Japanese company invented a self-adhesive PVC packaging film, made of PVC resin with a hybrid plasticizer, 50%~90% of the mixed plasticizer is citrate plasticizer, this product has been widely used
in Japan and South Korea.
ATBC is the main plasticizer of PVC film for food packaging, especially suitable for food packaging
with high fat content such as meat.
The PVDC film plasticized by ATBC not only has a thermal stability effect, but also has good heat shrinkage, starting to shrink at 50~60 °C, shrinkage rate reaches 20%~50% at 100 °C, the highest contraction force presented at 80 °C is 1.
3~1.
5MPa, and it has a high sealing capacity
when high frequency heat sealing.
ATBC, as the main plasticizer of PVDC for food packaging, is irreplaceable
by the general plasticizer DOP.

2.
Children's toys China is a major toy production and exporter, but since 2005, China's exported plastic toys
have been frequently recalled, causing huge economic losses, one of the main reasons is that the plasticizer content seriously exceeds the standard
.
To change this situation, environmentally friendly plastics
need to be promoted.
Because ATBC is non-toxic, odorless, good transparency and low water extraction rate, the plastic products plasticized by it have excellent processing performance, good heat sealing and convenient secondary processing, and are considered by the industry to be an ideal plasticizer
for children's toys.

3.
Medical products
plasticized by ATBC have good
high temperature and low temperature resistance.
Used for the outer packaging of drugs, the outer surface is elastic, not easy to break, and the drug wrapping effect is good
.
In high-grade artificial organ plastics, silicone rubber and other medical devices, ATBC is also added as an auxiliary agent abroad to improve the service life
of products.

ATBC plasticized PVC is used for medical treatment, mainly including infusion bottles, infusion bags, blood transfusion bags, peritoneal dialysis fluid bags, etc
.
PVC plastic infusion containers need to have no microorganisms penetrating during the storage of the solution, do not play a physical or chemical role with the solution, and cannot cause harm
to the human body.
Plastic blood bags should be colorless transparent, soft, airtight, sterile, non-toxic, sterilizable, the storage process of blood bag components in the anticoagulant or blood dissolution must meet the standard provisions, and to the greatest extent to limit the toxicity to the blood and the impact
on patients.
At present, the plasticizer commonly used in medical product packaging is DOP, but the toxicity of DOP in blood distractions has begun to attract people's attention, and it is inevitable
to restrict the use of DOP in the medical field 。 The hardness and 100% modulus of PVC plasticized by ATBC are almost the same as that of PVC plasticized by DOP, and the corrosion resistance and water permeability are also equivalent, but ATBC is easier to precipitate than DOP, but for disposable infusion sets, medical gloves, plasma bags and other medical PVC products that are used for no more than three weeks, a small amount of precipitated ATBC almost does not change the performance of the product, and has almost no impact
on the health of the user.
In foreign countries, as early as the 70s of the twentieth century, ATBC has been widely used in medical devices and is an ideal substitute
for phthalate plasticizers in the medical industry.

In recent years, ATBC has also directly entered the human body as a component of continuously released drugs, and Bray et al.
have studied the effect of plasticizers in the interaction between drugs (oxazocaine) and PVC, and believe that the permeability of benzocaine of PVC increases with the increase of plasticizer concentration and temperature, and the adsorption decreases with the increase of plasticizer concentration and temperature
.
ATBC has a greater
influence during adsorption and osmosis than DOP.

4.
Metal surface treatment
because ATBC has good solubility for many organic substances and resins, can improve the adhesion between polymers and metals, and the lubricating oil prepared by it has good lubricity
.
A steel company in the United States uses tinplate container material to be coated with citrate (including 5%~10% ATBC) as lubricating oil, the material is suitable for calendering and extrusion, and the surface of the container made by it is very smooth
.

5.
ATBC in clinical testing of personal care products and cosmetics is gentle and non-irritating, which can be used for plasticizing in cosmetics
and personal care products, and the concentration in nail products can reach 7%.

ATBC can be used as a plasticizer for film-forming components, so it can also be used as a skin conditioning agent, softener, and palliative agent
.
Mixing 0.
5%~20% ATBC with 0.
01%~5% antioxidant greatly enhances the antibacterial ability of the manufactured soap and increases the deodorization effect
.

6.
The oil displacement agent
citrate has three ester groups, which can be used as a displacement agent for tertiary oil recovery after compounding with surfactants, and can also be used as a wrapping material
for oilfield oil displacement agents.

7.
Other
ATBC as an excellent plasticizer can also be used to increase foamed PVC, cellulose resin and synthetic rubber, etc.
, and can also be used as a stabilizer for polyvinylidene chloride; ATBC is added as a plasticizer in the polylactic acid blend, which is conducive to polymer crystallization, improves impact resistance and accelerates degradation rate; In polyisobutylene-isoprene copolymer or butadiene styrene copolymer, in the presence of foaming agent, ATBC can be added to make chewing gum; In oil-filled polyurethane rubber, ATBC can be added to improve compatibility; The cellulose film plasticized with ATBC has low volatility loss and strong adhesion to metals; ATBC can also be used as an enzymatic reaction solvent, a stationary phase in chromatographic analysis, a foam remover for protein-containing liquids, a paper flavor enhancer, a rubber anti-scorch agent, etc.
, and is the most widely used variety
of citrate.

In recent years, affected by the EU REACH regulation, Taiwan's "plasticizer" incident, and plasticizers in amoxicillin, phthalate plasticizer manufacturers have suffered unprecedented blows
.
The restrictions on international environmental protection regulations for phthalate plasticizers continue to expand, and Japan, South Korea and other countries have successively introduced relevant regulations in 2011 to restrict the use of
phthalate plasticizers.
The development of green and environmentally friendly plasticizers is therefore more eye-catching, which provides development space
for the environmentally friendly plasticizer ATBC.